Scheduled notifications not working on iOS Flutter

Question

I'm using flutter_local_notifications to schedule notifications at specific times every day.

The user can select different time zones, it works on Android but doesn't work on iOS, as I don't have experience with iOS, I don't know how it handles notifications.

Future<void> _showNotification(
  BuildContext? context,
  NotificationDetails platformChannelSpecifics,
  Prayer prayer,
  DateTime dateTime) async {// dateTime is the time in another time zone, and time is the time passed to the zonedScheduled method
var time = _nextInstanceOfPrayer(dateTime);

if (time == null) {
  return;
}

await flutterLocalNotificationsPlugin.zonedSchedule(
  _getId(time, prayer: prayer.toString()),
  prayer.toStr(context!),
  _getPrayerText(prayer.toStr(context)),
  time,
  platformChannelSpecifics,
  androidAllowWhileIdle: true,
  uiLocalNotificationDateInterpretation:
      UILocalNotificationDateInterpretation.absoluteTime,
);}

And this method to get the time:

tzZone.TZDateTime? _nextInstanceOfPrayer(DateTime dateTime) {
final DateTime now = DateTime.now();

//converts time to specific location
tzZone.TZDateTime scheduledDate = tzZone.TZDateTime.from(
  dateTime.subtract(now.timeZoneOffset),
  tzZone.UTC,
);
if (scheduledDate.toUtc().isBefore(now.toUtc())) {
  return null;
}

return scheduledDate;}

What I'm trying is add notification at the time (time) in phone's local time, for example, the user selects a +5 GMT time zone (5:00PM) and the local time zone is say +2 GMT (2:00PM), I want to add a notification with the local time of (5:00PM +5 GMT) and show it on (5:00 +2 GMT).

I have tried to convert both times to UTC and show the notification on UTC - local time zone (as shown in the second code), the code shows there are pending notifications but when I change the time of the device it doesn't show anything.

Note: when I add a manual time after 5 seconds, it works perfectly

DateTime.now().add(Duration(seconds: 5));