CustomPreload.ts

@Injectable({
  providedIn: 'root'
})
export class CustomPreload implements PreloadingStrategy {
  preload(route: Route, load: (): Observable<any>): Observable<any> {
    // you implement this function somewhere, somehow
    if (isActiveCardRoute(route)) {
      // this will make it load immediately
      return load();
    } else {
      /* 
       * this will load the remaining modules after 5 seconds. You can possibly make a more
       * 'complex' logic to have it load sequentially or in bigger intervals to make sure
       * the app doesn't lag when loading
      */
      return timer(5000).pipe(
        switchMap(() => load())
      )
    }
  }
}