Is there an utility to keep certain apps from closing ? (with or without root)

Any external clock alarm app I have tried on my Android 11 phone shuts down automatically at a certain period of time (some hours), so I cannot use it as an alarm clock. I have tried to set those apps not battery optimized, of course, with no luck. Can it be achieved with some utility ? I have tried "auto memory manager" but it crashes at startup, and it's too old. Maybe with Tasker ? how ?... Some apps like termux or IRC for Android already implement it but e.g. Alarm clock for Heavy Sleepers shuts down, and I love this app because you can snooze it by turning upside down the phone, and also it can play radio streams...