1-game-web-app.page.ts

export class ProfilePage {
  ...
  
  shouldTriggerAppOpen = false;

  gameUrl = from(this.userService.getUserId()).pipe(
    mergeMap(
      ({ token: userIdToken } = { token = '' }) =>
        this.gameService.buildUrl(userIdToken)
    ),
    tap(url => {
      Browser.open(url);
      this.shouldTriggerAppOpen = false;
    }),
   );

   gameUrlHasError = this.gameUrl.catchError(
     gameUrlError => of(gameUrlError),
   );
}

game-web-app.page.html

<a (click)="shouldTriggerAppOpen = true">
  Open The Game
</a>

<ng-container *ngIf="shouldTriggerAppOpen">
  <ng-container *ngIf="gameUrl | async; else loadingOrError"></ng-container>
</ng-container>

<ng-template #loadingOrError>
  <error-message
    *ngIf="gameUrlHasError as error | async; else loading"
    [message]="error.message"
  ></error-message>
</ng-template>

<ng-template #loading>
  <loading-toast></loading-toast>
</ng-template>