how do i show success notification after page reload: like show success message after: $window.location.reload();

Think you either need the : https://docs.umbraco.com/umbraco-cms/reference/angular/services/eventsservice or the notificationService (or both for your goal), of which I cant find documenation for the angular variant of it.. You can show a red/green popup like this:

notificationsService.error("Error", "This went wrong");

notificationsService.error("Success", "Good job!");