I'm writing my own app for practicing the piano.
The goal is to make practicing fun, while also making steady progress.
I'm not a good player at all, and I've struggled with practice for years. But I have no problems playing (practicing) difficult video games, that require a lot of repetition (think Celeste).
I think I've identified two major reasons why I never enjoyed it:
1. Classical music notation (sheet music) is just awful. It goes against most modern principles of easy-to-grasp information design. So I've come up with my own notation that is much easier to read and can be generated from musicxml files.
2. Practicing takes too much decision making and discipline. If you want to make progress, you have to constantly remind yourself to practice the parts that you're not good at yet - this is a surprising amount of mental overhead and requires lots of discipline. So the app I wrote listens to you play via MIDI and keeps track of which segments of a piece you're already good at, and automatically gives you those you still need to practice more - zero decision making required. You just play whatever the app gives you and after a few weeks/months you're suddenly able to play the whole piece.
The app is no where near ready to be shown, but I'm confident at this point that the concept will work.
I've been planning a longer write up on this for a while, if you're interested in reading more about it, please let me know, that would be very motivating :)