I had the same problem on my Pixel 2 since the Android 9 beta. I ended up downloading System UI Tuner (https://play.google.com/store/apps/details?id=com.zacharee1.systemuituner) and forcing SSG3 into Immersive Mode.
Installing the Google Play version overtop of the Humble Bundle version should have kept premium. Can you double check on Google Play to see if there are any more updates you may be missing?
Progress should sync via Google Play if you are signed in. Some users backup using Helium as an extra backup: https://play.google.com/store/apps/details?id=com.koushikdutta.backup&hl=en