diff --git a/apps/client/eslint.config.cjs b/apps/client/eslint.config.cjs
index 96ecefd50..bcbe2c1c1 100644
--- a/apps/client/eslint.config.cjs
+++ b/apps/client/eslint.config.cjs
@@ -47,7 +47,9 @@ module.exports = [
   {
     files: ['**/*.ts', '**/*.tsx'],
     // Override or add rules here
-    rules: {}
+    rules: {
+      '@typescript-eslint/prefer-nullish-coalescing': 'error'
+    }
   },
   {
     files: ['**/*.js', '**/*.jsx'],
diff --git a/apps/client/jest.config.ts b/apps/client/jest.config.ts
index 04378bdbd..26d772e11 100644
--- a/apps/client/jest.config.ts
+++ b/apps/client/jest.config.ts
@@ -1,4 +1,3 @@
-/* eslint-disable */
 export default {
   displayName: 'client',
 
diff --git a/apps/client/src/app/components/admin-market-data/asset-profile-dialog/asset-profile-dialog.component.ts b/apps/client/src/app/components/admin-market-data/asset-profile-dialog/asset-profile-dialog.component.ts
index 967a289ef..c34e8eb78 100644
--- a/apps/client/src/app/components/admin-market-data/asset-profile-dialog/asset-profile-dialog.component.ts
+++ b/apps/client/src/app/components/admin-market-data/asset-profile-dialog/asset-profile-dialog.component.ts
@@ -550,7 +550,7 @@ export class GfAssetProfileDialogComponent implements OnInit {
         ) as Record<string, string>,
         locale:
           this.assetProfileForm.controls.scraperConfiguration.controls.locale
-            ?.value || undefined,
+            ?.value ?? undefined,
         mode:
           this.assetProfileForm.controls.scraperConfiguration.controls.mode
             ?.value ?? undefined,
@@ -599,7 +599,7 @@ export class GfAssetProfileDialogComponent implements OnInit {
       assetClass: this.assetProfileForm.controls.assetClass.value ?? undefined,
       assetSubClass:
         this.assetProfileForm.controls.assetSubClass.value ?? undefined,
-      comment: this.assetProfileForm.controls.comment.value || undefined,
+      comment: this.assetProfileForm.controls.comment.value ?? undefined,
       currency: this.assetProfileForm.controls.currency.value ?? undefined,
       dataGatheringFrequency:
         this.assetProfileForm.controls.dataGatheringFrequency.value ??
@@ -607,8 +607,8 @@ export class GfAssetProfileDialogComponent implements OnInit {
       isActive: isBoolean(this.assetProfileForm.controls.isActive.value)
         ? this.assetProfileForm.controls.isActive.value
         : undefined,
-      name: this.assetProfileForm.controls.name.value || undefined,
-      url: this.assetProfileForm.controls.url.value || undefined
+      name: this.assetProfileForm.controls.name.value ?? undefined,
+      url: this.assetProfileForm.controls.url.value ?? undefined
     };
 
     try {
@@ -743,7 +743,7 @@ export class GfAssetProfileDialogComponent implements OnInit {
           ) as Record<string, string>,
           locale:
             this.assetProfileForm.controls.scraperConfiguration.controls.locale
-              ?.value || undefined,
+              ?.value ?? undefined,
           mode: this.assetProfileForm.controls.scraperConfiguration.controls
             .mode?.value,
           selector:
diff --git a/apps/client/src/app/components/admin-overview/admin-overview.component.ts b/apps/client/src/app/components/admin-overview/admin-overview.component.ts
index 7374fb05c..62bc78df1 100644
--- a/apps/client/src/app/components/admin-overview/admin-overview.component.ts
+++ b/apps/client/src/app/components/admin-overview/admin-overview.component.ts
@@ -63,6 +63,7 @@ import {
   trashOutline
 } from 'ionicons/icons';
 import ms, { StringValue } from 'ms';
+import { NgxSkeletonLoaderModule } from 'ngx-skeleton-loader';
 
 @Component({
   changeDetection: ChangeDetectionStrategy.OnPush,
@@ -79,6 +80,7 @@ import ms, { StringValue } from 'ms';
     MatSnackBarModule,
     MatSlideToggleModule,
     MatTableModule,
+    NgxSkeletonLoaderModule,
     ReactiveFormsModule,
     RouterModule
   ],
@@ -102,6 +104,7 @@ export class GfAdminOverviewComponent implements OnInit {
   protected hasPermissionToToggleReadOnlyMode: boolean;
   protected readonly info: InfoItem;
   protected isDataGatheringEnabled: boolean;
+  protected isLoading = false;
   protected readonly permissions = permissions;
   protected systemMessage: SystemMessage;
   protected userCount: number;
@@ -320,6 +323,8 @@ export class GfAdminOverviewComponent implements OnInit {
   }
 
   private fetchAdminData() {
+    this.isLoading = true;
+
     this.adminService
       .fetchAdminData()
       .pipe(takeUntilDestroyed(this.destroyRef))
@@ -336,6 +341,8 @@ export class GfAdminOverviewComponent implements OnInit {
         this.userCount = userCount;
         this.version = version;
 
+        this.isLoading = false;
+
         this.changeDetectorRef.markForCheck();
       });
   }
diff --git a/apps/client/src/app/components/admin-overview/admin-overview.html b/apps/client/src/app/components/admin-overview/admin-overview.html
index 2fde94083..7e05600a6 100644
--- a/apps/client/src/app/components/admin-overview/admin-overview.html
+++ b/apps/client/src/app/components/admin-overview/admin-overview.html
@@ -248,6 +248,17 @@
                   mat-row
                 ></tr>
               </table>
+
+              @if (isLoading) {
+                <ngx-skeleton-loader
+                  animation="pulse"
+                  class="px-4 py-3"
+                  [theme]="{
+                    height: '1.5rem',
+                    width: '100%'
+                  }"
+                />
+              }
             </div>
           </mat-card-content>
           <mat-card-actions align="end">
diff --git a/apps/client/src/app/components/admin-users/admin-users.component.ts b/apps/client/src/app/components/admin-users/admin-users.component.ts
index 4b9848cf8..305c48dcf 100644
--- a/apps/client/src/app/components/admin-users/admin-users.component.ts
+++ b/apps/client/src/app/components/admin-users/admin-users.component.ts
@@ -8,6 +8,7 @@ import { UserService } from '@ghostfolio/client/services/user/user.service';
 import { DEFAULT_LOCALE, DEFAULT_PAGE_SIZE } from '@ghostfolio/common/config';
 import { ConfirmationDialogType } from '@ghostfolio/common/enums';
 import {
+  canDeleteUser,
   getCountryName,
   getDateFnsLocale,
   getDateFormatString,
@@ -91,6 +92,7 @@ export class GfAdminUsersComponent implements OnInit {
   >();
   protected defaultDateFormat: string;
   protected displayedColumns: string[] = [];
+  protected readonly canDeleteUser = canDeleteUser;
   protected readonly getCountryName = getCountryName;
   protected readonly getEmojiFlag = getEmojiFlag;
   protected hasPermissionForSubscription: boolean;
diff --git a/apps/client/src/app/components/admin-users/admin-users.html b/apps/client/src/app/components/admin-users/admin-users.html
index 668f39557..7e7e5edeb 100644
--- a/apps/client/src/app/components/admin-users/admin-users.html
+++ b/apps/client/src/app/components/admin-users/admin-users.html
@@ -241,7 +241,12 @@
                 <hr class="m-0" />
                 <button
                   mat-menu-item
-                  [disabled]="element.id === user?.id"
+                  [disabled]="
+                    !canDeleteUser({
+                      currentUserId: user?.id,
+                      userId: element.id
+                    })
+                  "
                   (click)="onDeleteUser(element.id)"
                 >
                   <span class="align-items-center d-flex">
diff --git a/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.component.ts b/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.component.ts
index 04d89c5a6..9e341037a 100644
--- a/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.component.ts
+++ b/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.component.ts
@@ -1,4 +1,8 @@
-import { getCountryName, getSum } from '@ghostfolio/common/helper';
+import {
+  canDeleteUser,
+  getCountryName,
+  getSum
+} from '@ghostfolio/common/helper';
 import { AdminUserResponse } from '@ghostfolio/common/interfaces';
 import { AdminService, DataService } from '@ghostfolio/ui/services';
 import { GfValueComponent } from '@ghostfolio/ui/value';
@@ -50,6 +54,7 @@ import {
 })
 export class GfUserDetailDialogComponent implements OnInit {
   protected readonly baseCurrency: string;
+  protected readonly canDeleteUser = canDeleteUser;
   protected readonly getCountryName = getCountryName;
   protected readonly subscriptionsDataSource =
     new MatTableDataSource<Subscription>();
diff --git a/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.html b/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.html
index f549b476f..e2cdb66a5 100644
--- a/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.html
+++ b/apps/client/src/app/components/user-detail-dialog/user-detail-dialog.html
@@ -16,7 +16,12 @@
     <button
       mat-menu-item
       type="button"
-      [disabled]="this.data.currentUserId === this.data.userId"
+      [disabled]="
+        !canDeleteUser({
+          currentUserId: data.currentUserId,
+          userId: data.userId
+        })
+      "
       (click)="deleteUser()"
     >
       <ng-container i18n>Delete</ng-container>
diff --git a/apps/client/src/app/pages/accounts/create-or-update-account-dialog/create-or-update-account-dialog.component.ts b/apps/client/src/app/pages/accounts/create-or-update-account-dialog/create-or-update-account-dialog.component.ts
index ca88120ca..d27b5ceae 100644
--- a/apps/client/src/app/pages/accounts/create-or-update-account-dialog/create-or-update-account-dialog.component.ts
+++ b/apps/client/src/app/pages/accounts/create-or-update-account-dialog/create-or-update-account-dialog.component.ts
@@ -200,12 +200,12 @@ export class GfCreateOrUpdateAccountDialogComponent {
   protected async onSubmit() {
     const account: CreateAccountDto | UpdateAccountDto = {
       balance: this.accountForm.get('balance')?.value,
-      comment: this.accountForm.get('comment')?.value || null,
+      comment: this.accountForm.get('comment')?.value ?? null,
       currency: this.accountForm.get('currency')?.value,
       id: this.accountForm.get('accountId')?.value,
       isExcluded: this.accountForm.get('isExcluded')?.value,
       name: this.accountForm.get('name')?.value,
-      platformId: this.accountForm.get('platformId')?.value?.id || null,
+      platformId: this.accountForm.get('platformId')?.value?.id ?? null,
       tags: this.accountForm
         .get('tags')
         ?.value?.filter(({ id }: Tag) => {
diff --git a/apps/client/src/app/pages/portfolio/activities/create-or-update-activity-dialog/create-or-update-activity-dialog.component.ts b/apps/client/src/app/pages/portfolio/activities/create-or-update-activity-dialog/create-or-update-activity-dialog.component.ts
index be9ac7b04..10bc7ccc8 100644
--- a/apps/client/src/app/pages/portfolio/activities/create-or-update-activity-dialog/create-or-update-activity-dialog.component.ts
+++ b/apps/client/src/app/pages/portfolio/activities/create-or-update-activity-dialog/create-or-update-activity-dialog.component.ts
@@ -493,7 +493,7 @@ export class GfCreateOrUpdateActivityDialogComponent {
       accountId: this.activityForm.get('accountId')?.value,
       assetClass: this.activityForm.get('assetClass')?.value,
       assetSubClass: this.activityForm.get('assetSubClass')?.value,
-      comment: this.activityForm.get('comment')?.value || null,
+      comment: this.activityForm.get('comment')?.value ?? null,
       currency: this.activityForm.get('currency')?.value,
       customCurrency: this.activityForm.get('currencyOfUnitPrice')?.value,
       dataSource: ['FEE', 'INTEREST', 'LIABILITY', 'VALUABLE'].includes(
diff --git a/apps/client/src/app/services/user/user.service.ts b/apps/client/src/app/services/user/user.service.ts
index 52f33dc5a..d58f77c3e 100644
--- a/apps/client/src/app/services/user/user.service.ts
+++ b/apps/client/src/app/services/user/user.service.ts
@@ -192,6 +192,6 @@ export class UserService extends ObservableStore<UserStoreState> {
       return throwError(errMessage);
     }
 
-    return throwError(error || 'Server error');
+    return throwError(error ?? 'Server error');
   }
 }
diff --git a/libs/common/src/lib/helper.ts b/libs/common/src/lib/helper.ts
index 42aec19ac..9a32927e2 100644
--- a/libs/common/src/lib/helper.ts
+++ b/libs/common/src/lib/helper.ts
@@ -163,6 +163,16 @@ export function canDeleteAssetProfile({
   );
 }
 
+export function canDeleteUser({
+  currentUserId,
+  userId
+}: {
+  currentUserId: string;
+  userId: string;
+}): boolean {
+  return currentUserId !== userId;
+}
+
 export function capitalize(aString: string) {
   return aString.charAt(0).toUpperCase() + aString.slice(1).toLowerCase();
 }
diff --git a/libs/ui/eslint.config.cjs b/libs/ui/eslint.config.cjs
index e21452b5f..65d17debd 100644
--- a/libs/ui/eslint.config.cjs
+++ b/libs/ui/eslint.config.cjs
@@ -41,7 +41,8 @@ module.exports = [
           }
         ],
         '@angular-eslint/prefer-inject': 'off',
-        '@angular-eslint/prefer-standalone': 'off'
+        '@angular-eslint/prefer-standalone': 'off',
+        '@typescript-eslint/prefer-nullish-coalescing': 'error'
       },
       languageOptions: {
         parserOptions: {
diff --git a/libs/ui/src/lib/activities-table/activities-table.component.ts b/libs/ui/src/lib/activities-table/activities-table.component.ts
index b1bfcf686..fba02ad30 100644
--- a/libs/ui/src/lib/activities-table/activities-table.component.ts
+++ b/libs/ui/src/lib/activities-table/activities-table.component.ts
@@ -267,7 +267,7 @@ export class GfActivitiesTableComponent implements AfterViewInit, OnInit {
 
   public isExcludedFromAnalysis(activity: Activity) {
     return (
-      (activity.account && isAccountExcluded(activity.account)) ||
+      (activity.account && isAccountExcluded(activity.account)) ??
       activity.tags?.some(({ id }) => {
         return id === TAG_ID_EXCLUDE_FROM_ANALYSIS;
       }) === true