Ich habe aufgrund folgender Anleitung von XDA auch Playstore UND Notifications:
1a. Run following commands using ADB:
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
1b. Open Settings - Apps - App Launch
Tap the three dots, select "Show system Processes".
Search For Google Services Framework.
Change from Manage Automatically- To Manage Manually. Deselect Options "Auto-launch" and "Run in background". Only secondary launch remains selected.
2. Put phone in airplane mode. It's very important!
3. Open Settings, go to Apps, Apps, tap three dots, select Show system processes, find Google Services Framework. Open it.
4. If you have frozen Gsf defrost it (enable).
5. Stop it if it's running. Go to Storage, clear cache, clear data. Stop it again if necessary.
6. Restart the phone.
7. Do not disable airplane mode yet! Wait few minutes in airplane mode or check with Device ID app if you see your GSF ID.
8. Disable airplane mode and check play store. If you see error message, close it from task list and try again.
If you restart the phone without enabling airplane mode first all you have to do is redo above guide starting from point 2.
If you see play protect notifications do not panic! Enable airplane mode, go to settings, apps, apps, find Google framework services, goto storage, stop it, clear cache, clear data, restart your phone then you should be good.