You’re right, since Android O, AlarmManager can be unreliable for scheduled notifications if the app is closed and battery optimization is enabled. I have tested this on my Android 13 device, which has two power-saving options: "Power Saving mode" and "Super Power Saving mode". In "Power Saving mode" with fewer restrictions, notifications are allowed, whereas the "Super Power Saving mode" does not allow them. I found it manageable to implement in my project considering these modes.

I appreciate your feedback and will come up with the best optimized way in a short time.