Each time I restore my apps using my Google account I find out that some apps were just left out; the apps were no longer available on the Google Play Store.
How can I confirm that all apps installed via the Google play store are still available on the Google Play Store, so that when I restore my backup via my Google account I don't have apps missing.
I would do this by using an Apk Exporter to store the apps which are no longer available on the Google Play Store.
pm list packages
and a small script it would be possible to filter out apps that are missing in Play Store. May be there is already an app that uses this way to check the installed apps but I don't know such an app.