Very interesting - Piano Maestro is the advanced learning app by the same company that does the beginner "gamey" app called SimplyPiano (which I use).

Cubasis works on mobile - https://play.google.com/store/apps/details?id=com.steinberg.... as well as other options like ntrack 8 . There is also latency comparisons for android devices here https://ntrack.com/android-latency/devices