Android. Show notification in exact time

Question

I have a question, that has been asked here many times, but I still can't find correct solution.

I need to implement in an app a feature, that will show notification in exact time (for example, show notification every 30 minutes).

I tried use::

1. Standard notifications with High Priority flag
2. Standard notifications with High Priority flag and disabled doze optimization
3. Notifications with Alarm Manager
4. Alarm Manager and disabled Doze

Points 2 and 4 are working well, but not enough. In this case notification could be delayed for 3 minutes (if phone is not used in a long time period).

So, the question is :: Is there any way to show notifications in exact time without delay larger than 1 min ??

P.S. It is said everywhere, that using of AlarmManager will drain you battery much. I didn't find that.