diff --git a/ui/app/components/auth-config-form/options.js b/ui/app/components/auth-config-form/options.js
index 923ac27f68..da9e9b8f33 100644
--- a/ui/app/components/auth-config-form/options.js
+++ b/ui/app/components/auth-config-form/options.js
@@ -47,7 +47,7 @@ export default AuthConfigComponent.extend({
         // because we're not calling model.save the model never updates with
         // the error.  Forcing the error message by manually setting the errorMessage
         try {
-          this.model.set('errorMessage', err.errors.firstObject);
+          this.model.set('errorMessage', err.errors?.join(','));
         } catch {
           // do nothing
         }
diff --git a/ui/app/components/auth-form.js b/ui/app/components/auth-form.js
index 76748f7cc9..7e5248186a 100644
--- a/ui/app/components/auth-form.js
+++ b/ui/app/components/auth-form.js
@@ -121,7 +121,7 @@ export default Component.extend(DEFAULTS, {
   },
 
   firstMethod() {
-    const firstMethod = this.methodsToShow.firstObject;
+    const firstMethod = this.methodsToShow[0];
     if (!firstMethod) return;
     // prefer backends with a path over those with a type
     return firstMethod.path || firstMethod.type;
@@ -166,7 +166,7 @@ export default Component.extend(DEFAULTS, {
     return templateName;
   }),
 
-  hasCSPError: alias('csp.connectionViolations.firstObject'),
+  hasCSPError: alias('csp.connectionViolations'),
 
   cspErrorText: `This is a standby Vault node but can't communicate with the active node via request forwarding. Sign in at the active node to use the Vault UI.`,
 
diff --git a/ui/app/components/identity/lookup-input.js b/ui/app/components/identity/lookup-input.js
index 96a4986b5a..b683f44001 100644
--- a/ui/app/components/identity/lookup-input.js
+++ b/ui/app/components/identity/lookup-input.js
@@ -27,7 +27,7 @@ export default Component.extend({
     this._super(...arguments);
     this.store.findAll('auth-method').then((methods) => {
       this.set('authMethods', methods);
-      this.set('aliasMountAccessor', methods.get('firstObject.accessor'));
+      this.set('aliasMountAccessor', methods[0].accessor);
     });
   },
 
diff --git a/ui/app/components/mount-accessor-select.js b/ui/app/components/mount-accessor-select.js
index bf72745544..84b6d34400 100644
--- a/ui/app/components/mount-accessor-select.js
+++ b/ui/app/components/mount-accessor-select.js
@@ -45,7 +45,7 @@ export default class MountAccessorSelect extends Component {
   @task *authMethods() {
     const methods = yield this.store.findAll('auth-method');
     if (!this.args.value && !this.args.noDefault) {
-      const getValue = methods.get('firstObject.accessor');
+      const getValue = methods[0].accessor;
       this.args.onChange(getValue);
     }
     return methods;
diff --git a/ui/app/components/transit-key-actions.hbs b/ui/app/components/transit-key-actions.hbs
index 26e394ee49..d9070392a9 100644
--- a/ui/app/components/transit-key-actions.hbs
+++ b/ui/app/components/transit-key-actions.hbs
@@ -2,7 +2,6 @@
   Copyright (c) HashiCorp, Inc.
   SPDX-License-Identifier: BUSL-1.1
 ~}}
-
 <div {{did-update this.updateProps @selectedAction}}>
   <MessageError @errorMessage={{this.errors}} />
 
@@ -109,7 +108,7 @@
       @submitIsRunning={{this.doSubmit.isRunning}}
       data-test-transit-action={{@selectedAction}}
     />
-  {{else if (or (eq @selectedAction "export") (eq @key.supportedActions.firstObject "export"))}}
+  {{else if (or (eq @selectedAction "export") (eq (get @key.supportedActions 0) "export"))}}
     <TransitKeyAction::Export
       @key={{@key}}
       @keys={{this.props.keys}}
diff --git a/ui/app/routes/vault/cluster/secrets/backend.js b/ui/app/routes/vault/cluster/secrets/backend.js
index 4424b684cd..5e3a1942e1 100644
--- a/ui/app/routes/vault/cluster/secrets/backend.js
+++ b/ui/app/routes/vault/cluster/secrets/backend.js
@@ -21,7 +21,7 @@ export default Route.extend({
       })
       .then((model) => {
         if (model) {
-          return model.get('firstObject');
+          return model[0];
         }
       });
   },
diff --git a/ui/app/routes/vault/cluster/secrets/backend/actions.js b/ui/app/routes/vault/cluster/secrets/backend/actions.js
index 977cbff9dd..98a5981921 100644
--- a/ui/app/routes/vault/cluster/secrets/backend/actions.js
+++ b/ui/app/routes/vault/cluster/secrets/backend/actions.js
@@ -30,6 +30,6 @@ export default EditBase.extend({
   setupController(controller, model) {
     this._super(...arguments);
     const { selectedAction } = this.paramsFor(this.routeName);
-    controller.set('selectedAction', selectedAction || model.secret.get('supportedActions.firstObject'));
+    controller.set('selectedAction', selectedAction || model.secret.supportedActions[0]);
   },
 });
diff --git a/ui/app/routes/vault/cluster/settings/auth/configure/index.js b/ui/app/routes/vault/cluster/settings/auth/configure/index.js
index 7cd5138ee2..67db7cabb6 100644
--- a/ui/app/routes/vault/cluster/settings/auth/configure/index.js
+++ b/ui/app/routes/vault/cluster/settings/auth/configure/index.js
@@ -12,7 +12,7 @@ export default class SettingsAuthConfigureRoute extends Route {
 
   beforeModel() {
     const model = this.modelFor('vault.cluster.settings.auth.configure');
-    const section = tabsForAuthSection([model]).firstObject.routeParams.lastObject;
+    const section = tabsForAuthSection([model])[0].routeParams.lastObject;
     return this.router.transitionTo('vault.cluster.settings.auth.configure.section', section);
   }
 }
diff --git a/ui/app/routes/vault/cluster/settings/configure-secret-backend.js b/ui/app/routes/vault/cluster/settings/configure-secret-backend.js
index d19bb624d8..a320c8104f 100644
--- a/ui/app/routes/vault/cluster/settings/configure-secret-backend.js
+++ b/ui/app/routes/vault/cluster/settings/configure-secret-backend.js
@@ -15,7 +15,7 @@ export default Route.extend({
   model() {
     const { backend } = this.paramsFor(this.routeName);
     return this.store.query('secret-engine', { path: backend }).then((modelList) => {
-      const model = modelList && modelList.get('firstObject');
+      const model = modelList && modelList[0];
       if (!model || !CONFIGURABLE_BACKEND_TYPES.includes(model.get('type'))) {
         const error = new AdapterError();
         set(error, 'httpStatus', 404);
diff --git a/ui/app/services/csp-event.js b/ui/app/services/csp-event.js
index 253b7b8be4..b53ccb9681 100644
--- a/ui/app/services/csp-event.js
+++ b/ui/app/services/csp-event.js
@@ -14,7 +14,7 @@ export default Service.extend({
     return [];
   }),
   connectionViolations: computed('events.@each.violatedDirective', function () {
-    return this.events.filter((e) => e.violatedDirective.startsWith('connect-src'));
+    return this.events.some((e) => e.violatedDirective.startsWith('connect-src'));
   }),
 
   attach() {
diff --git a/ui/lib/core/addon/components/search-select-with-modal.js b/ui/lib/core/addon/components/search-select-with-modal.js
index 3ebcad12a0..313f148621 100644
--- a/ui/lib/core/addon/components/search-select-with-modal.js
+++ b/ui/lib/core/addon/components/search-select-with-modal.js
@@ -131,7 +131,7 @@ export default class SearchSelectWithModal extends Component {
 
   @action
   handleChange() {
-    if (this.selectedOptions.length && typeof this.selectedOptions.firstObject === 'object') {
+    if (this.selectedOptions.length && typeof this.selectedOptions[0] === 'object') {
       this.args.onChange(Array.from(this.selectedOptions, (option) => option.id));
     } else {
       this.args.onChange(this.selectedOptions);
@@ -139,7 +139,7 @@ export default class SearchSelectWithModal extends Component {
   }
 
   shouldShowCreate(id, searchResults) {
-    if (searchResults && searchResults.length && searchResults.firstObject.groupName) {
+    if (searchResults && searchResults.length && searchResults[0].groupName) {
       return !searchResults.some((group) => group.options.find((opt) => opt.id === id));
     }
     const existingOption =
diff --git a/ui/lib/core/addon/components/search-select.js b/ui/lib/core/addon/components/search-select.js
index eb65bde171..f42dd2f27e 100644
--- a/ui/lib/core/addon/components/search-select.js
+++ b/ui/lib/core/addon/components/search-select.js
@@ -196,7 +196,7 @@ export default class SearchSelect extends Component {
 
   @action
   handleChange() {
-    if (this.selectedOptions.length && typeof this.selectedOptions.firstObject === 'object') {
+    if (this.selectedOptions.length && typeof this.selectedOptions[0] === 'object') {
       this.args.onChange(
         Array.from(this.selectedOptions, (option) =>
           this.args.passObject ? this.customizeObject(option) : option.id
@@ -208,7 +208,7 @@ export default class SearchSelect extends Component {
   }
 
   shouldShowCreate(id, searchResults) {
-    if (searchResults && searchResults.length && searchResults.firstObject.groupName) {
+    if (searchResults && searchResults.length && searchResults[0].groupName) {
       return !searchResults.some((group) => group.options.find((opt) => opt.id === id));
     }
     const existingOption =
diff --git a/ui/lib/kmip/addon/templates/components/edit-form-kmip-role.hbs b/ui/lib/kmip/addon/templates/components/edit-form-kmip-role.hbs
index 0266f1ba69..3aea47a1d8 100644
--- a/ui/lib/kmip/addon/templates/components/edit-form-kmip-role.hbs
+++ b/ui/lib/kmip/addon/templates/components/edit-form-kmip-role.hbs
@@ -37,7 +37,7 @@
         <hr />
         <div class="is-flex">
           <div class="kmip-role-allowed-operations">
-            {{#each-in this.model.operationFormFields.firstObject as |groupName fieldsInGroup|}}
+            {{#each-in (get this.model.operationFormFields 0) as |groupName fieldsInGroup|}}
               <h4 class="title is-7">{{groupName}}</h4>
               {{#each fieldsInGroup as |attr|}}
                 <FormField
diff --git a/ui/lib/pki/addon/components/pki-key-parameters.ts b/ui/lib/pki/addon/components/pki-key-parameters.ts
index 9e920ab079..5bea31a4ed 100644
--- a/ui/lib/pki/addon/components/pki-key-parameters.ts
+++ b/ui/lib/pki/addon/components/pki-key-parameters.ts
@@ -56,7 +56,9 @@ export default class PkiKeyParameters extends Component<Args> {
 
     if (name === 'keyType' && Object.keys(KEY_BITS_OPTIONS)?.includes(selection)) {
       const bitOptions = KEY_BITS_OPTIONS[selection as keyof TypeOptions];
-      this.args.model.keyBits = bitOptions?.firstObject;
+      if (bitOptions) {
+        this.args.model.keyBits = bitOptions[0];
+      }
     }
   }
 
diff --git a/ui/lib/pki/addon/routes/configuration/index.js b/ui/lib/pki/addon/routes/configuration/index.js
index 64b6381fae..7d01102c28 100644
--- a/ui/lib/pki/addon/routes/configuration/index.js
+++ b/ui/lib/pki/addon/routes/configuration/index.js
@@ -16,7 +16,7 @@ export default class ConfigurationIndexRoute extends Route {
   async fetchMountConfig(backend) {
     const mountConfig = await this.store.query('secret-engine', { path: backend });
     if (mountConfig) {
-      return mountConfig.get('firstObject');
+      return mountConfig[0];
     }
   }
 
diff --git a/ui/lib/pki/addon/templates/keys/index.hbs b/ui/lib/pki/addon/templates/keys/index.hbs
index 09db5994a9..dd077ae68d 100644
--- a/ui/lib/pki/addon/templates/keys/index.hbs
+++ b/ui/lib/pki/addon/templates/keys/index.hbs
@@ -8,9 +8,9 @@
 <Page::PkiKeyList
   @keyModels={{this.model.keyModels}}
   @mountPoint={{this.mountPoint}}
-  @canImportKey={{this.model.keyModels.firstObject.canImportKey}}
-  @canGenerateKey={{this.model.keyModels.firstObject.canGenerateKey}}
-  @canRead={{this.model.keyModels.firstObject.canRead}}
-  @canEdit={{this.model.keyModels.firstObject.canEdit}}
+  @canImportKey={{(get (get this.model.keyModels 0) "canImportKey")}}
+  @canGenerateKey={{(get (get this.model.keyModels 0) "canGenerateKey")}}
+  @canRead={{(get (get this.model.keyModels 0) "canRead")}}
+  @canEdit={{(get (get this.model.keyModels 0) "canEdit")}}
   @hasConfig={{this.model.hasConfig}}
 />
\ No newline at end of file
diff --git a/ui/tests/integration/components/kubernetes/page/roles-test.js b/ui/tests/integration/components/kubernetes/page/roles-test.js
index 67e9a4b4ca..59899983ab 100644
--- a/ui/tests/integration/components/kubernetes/page/roles-test.js
+++ b/ui/tests/integration/components/kubernetes/page/roles-test.js
@@ -92,9 +92,7 @@ module('Integration | Component | kubernetes | Page::Roles', function (hooks) {
   test('it should render roles list', async function (assert) {
     await this.renderComponent();
     assert.dom('[data-test-list-item-content] svg').hasClass('flight-icon-user', 'List item icon renders');
-    assert
-      .dom('[data-test-list-item-content]')
-      .hasText(this.roles.firstObject.name, 'List item name renders');
+    assert.dom('[data-test-list-item-content]').hasText(this.roles[0].name, 'List item name renders');
     await click('[data-test-popup-menu-trigger]');
     assert.dom('[data-test-details]').hasText('Details', 'Details link renders in menu');
     assert.dom('[data-test-edit]').hasText('Edit', 'Edit link renders in menu');
diff --git a/ui/tests/integration/components/ldap/page/libraries-test.js b/ui/tests/integration/components/ldap/page/libraries-test.js
index 42c27c99af..32ff5450cb 100644
--- a/ui/tests/integration/components/ldap/page/libraries-test.js
+++ b/ui/tests/integration/components/ldap/page/libraries-test.js
@@ -93,7 +93,7 @@ module('Integration | Component | ldap | Page::Libraries', function (hooks) {
     await this.renderComponent();
 
     assert.dom('[data-test-list-item-content] svg').hasClass('flight-icon-folder', 'List item icon renders');
-    assert.dom('[data-test-library]').hasText(this.libraries.firstObject.name, 'List item name renders');
+    assert.dom('[data-test-library]').hasText(this.libraries[0].name, 'List item name renders');
 
     await click('[data-test-popup-menu-trigger]');
     assert.dom('[data-test-edit]').hasText('Edit', 'Edit link renders in menu');
diff --git a/ui/tests/integration/components/ldap/page/roles-test.js b/ui/tests/integration/components/ldap/page/roles-test.js
index 97d293a2de..ff5807992f 100644
--- a/ui/tests/integration/components/ldap/page/roles-test.js
+++ b/ui/tests/integration/components/ldap/page/roles-test.js
@@ -95,12 +95,10 @@ module('Integration | Component | ldap | Page::Roles', function (hooks) {
     await this.renderComponent();
 
     assert.dom('[data-test-list-item-content] svg').hasClass('flight-icon-user', 'List item icon renders');
-    assert
-      .dom('[data-test-role="static-test"]')
-      .hasText(this.roles.firstObject.name, 'List item name renders');
+    assert.dom('[data-test-role="static-test"]').hasText(this.roles[0].name, 'List item name renders');
     assert
       .dom('[data-test-role-type-badge="static-test"]')
-      .hasText(this.roles.firstObject.type, 'List item type badge renders');
+      .hasText(this.roles[0].type, 'List item type badge renders');
 
     await click('[data-test-popup-menu-trigger]');
     assert.dom('[data-test-edit]').hasText('Edit', 'Edit link renders in menu');
diff --git a/ui/tests/integration/components/mfa-login-enforcement-form-test.js b/ui/tests/integration/components/mfa-login-enforcement-form-test.js
index dfe1e3ee64..b605d6d523 100644
--- a/ui/tests/integration/components/mfa-login-enforcement-form-test.js
+++ b/ui/tests/integration/components/mfa-login-enforcement-form-test.js
@@ -141,7 +141,8 @@ module('Integration | Component | mfa-login-enforcement-form', function (hooks)
     await click('[data-test-mlef-save]');
     assert.true(this.didSave, 'onSave callback triggered');
     assert.strictEqual(this.model.name, 'bar', 'Name property set on model');
-    assert.strictEqual(this.model.mfa_methods.firstObject.id, '123456', 'Mfa method added to model');
+    const methods = await this.model.mfa_methods; //hasManyPromise
+    assert.strictEqual(methods[0].id, '123456', 'Mfa method added to model');
     assert.deepEqual(
       this.model.auth_method_accessors,
       ['auth_userpass_1234'],
diff --git a/ui/tests/integration/components/pki/pki-generate-csr-test.js b/ui/tests/integration/components/pki/pki-generate-csr-test.js
index 3b432d9fc5..7f4d6aa3f2 100644
--- a/ui/tests/integration/components/pki/pki-generate-csr-test.js
+++ b/ui/tests/integration/components/pki/pki-generate-csr-test.js
@@ -72,7 +72,7 @@ module('Integration | Component | pki-generate-csr', function (hooks) {
     await fillIn('[data-test-input="commonName"]', 'foo');
     await click('[data-test-save]');
 
-    const savedRecord = this.store.peekAll('pki/action').firstObject;
+    const savedRecord = this.store.peekAll('pki/action')[0];
     assert.false(savedRecord.isNew, 'record is saved');
   });
 
diff --git a/ui/tests/unit/adapters/ldap/role-test.js b/ui/tests/unit/adapters/ldap/role-test.js
index d8c4dcfac5..cb8c50dc4e 100644
--- a/ui/tests/unit/adapters/ldap/role-test.js
+++ b/ui/tests/unit/adapters/ldap/role-test.js
@@ -33,7 +33,7 @@ module('Unit | Adapter | ldap/role', function (hooks) {
 
     this.models = await this.store.query('ldap/role', { backend: 'ldap-test' });
 
-    const model = this.models.firstObject;
+    const model = this.models[0];
     assert.strictEqual(this.models.length, 2, 'Returns responses from both endpoints');
     assert.strictEqual(model.backend, 'ldap-test', 'Backend value is set on records returned from query');
     // sorted alphabetically by name so dynamic should be first
diff --git a/ui/tests/unit/serializers/transit-key-test.js b/ui/tests/unit/serializers/transit-key-test.js
index 2812373ac2..96d533ec9c 100644
--- a/ui/tests/unit/serializers/transit-key-test.js
+++ b/ui/tests/unit/serializers/transit-key-test.js
@@ -73,23 +73,15 @@ module('Unit | Serializer | transit-key', function (hooks) {
     const aesExpected = AES.data.keys[1] * 1000;
     const chachaExpected = CHACHA.data.keys[1] * 1000;
     const aesData = serializer.normalizeSecrets({ ...AES });
-    assert.strictEqual(aesData.firstObject.keys[1], aesExpected, 'converts seconds to millis for aes keys');
+    assert.strictEqual(aesData[0].keys[1], aesExpected, 'converts seconds to millis for aes keys');
 
     const chachaData = serializer.normalizeSecrets({ ...CHACHA });
-    assert.strictEqual(
-      chachaData.firstObject.keys[1],
-      chachaExpected,
-      'converts seconds to millis for chacha keys'
-    );
+    assert.strictEqual(chachaData[0].keys[1], chachaExpected, 'converts seconds to millis for chacha keys');
   });
 
   test('it includes backend from the payload on the normalized data', function (assert) {
     const serializer = this.owner.lookup('serializer:transit-key');
     const data = serializer.normalizeSecrets({ ...AES });
-    assert.strictEqual(
-      data.firstObject.backend,
-      'its-a-transit',
-      'pulls backend from the payload onto the data'
-    );
+    assert.strictEqual(data[0].backend, 'its-a-transit', 'pulls backend from the payload onto the data');
   });
 });