This is what works for me on my FireTV and Android phones:
- Turn off auto-update for apps
1.a - Optional: Open Apps in the Settings and Force Stop the app, clear cache, clear data, restart - Uninstall the existing version of Plex
- Enable ‘install unknown 3rd party apps’ in Settings.
- Head over to Plex for Android - #410 by akila_plex
- Download and install Plex for Android 8.27.2 from Dec '21. This is the last version that works on my Android devices.
- It’s unreal that this issue hasn’t been fixed!