This app will also work with Companion on Android < 11. On Android 11+ the APK must be built as QUERY_ALL_PACKAGES is not declared in the AI2 Companion app (but is required on Android 11+). If the app is to be published in the Play Store, this permission must be approved by Google (requested using a form).
What is the reason for this backup of (all) applications? And why should this backup be done via the device that is to be backed up?
There are numerous (external) applications that can be used to do this and save to an external data medium.