There are times when I don't want the OS to kill an app, and the OS can often fail in this aspect, causing loss of control.
However even more frustratingly, I've increasingly noticed that apps I only need rarely, maybe once a day, once a month, once a year, will still run in the background even with setting the app's battery settings in the OS to restricted.
There is _nothing_ I can do to stop them from running, except uninstall them, but that's a pain for apps I have no choice but to use, even if rarely.
This is a problem even on GrapheneOS which increases user control. You could temporarily disable apps, but it is such a tedious process that uninstalling might be easier.