Thank you!
This actually looks very relevant [1]:
> Even disabling the system battery restrictions does not save the app from being killed. Let's find out, if it is a bug or a feature... Here you can read more details
I have Samsung s21; after years of fighting it (3 samsungs) I'm welcome to a bug explanation
- [1] https://dontkillmyapp.com/samsung#:~:text=Even%20disabling%2...