@mmarkq -> ADB Commands work well on your device?
I don't understand anything about ADB commands but I ask if instead of the word "ignore" it should be changed to another command like "kill" or "disabled" ... maybe.
On the other hand, if it works well for you, perfect, but if not, would something be missing in those commands?
adb shell
cmd appops set com.google.android.gsf RUN_IN_BACKGROUND ignore
cmd appops set com.google.android.gsf RUN_ANY_IN_BACKGROUND ignore
cmd appops write-settings
I attach you a screenshot from now. As you can see at GSF properties the Memory is greyed out, but some minutes ago increased from 190 Kb to 460 ... and started Play Protect errors ... but Memory stays greyed out ....