from now on my android ports of Ren'Py games have a 2nd, persistent save location like windows. if you uninstall an app, the save files and persistent data remain intact.
therefore the app needs the permission to access the public external storage (or a new one on Android 11 ), because it has to read and write outside its own external storage directories.
you have to grant the permission or the app is shut down.
have fun and please report problems (you can reach me