now with PUSH Notifications: https://github.com/zoff99/ToxAndroidRefImpl/blob/zoff99/dev003/PUSH_NOTIFICATION.md

SYSTEM_ALERT_WINDOW permission is only needed because starting with Android 10 Google does not allow an app to autostart after boot and show a password screen.

Android does not allow it any other way.

See: https://developer.android.com/guide/components/activities/background-starts

Visit https://dontkillmyapp.com/ to find more infos on properly running in the background.