For those interested, I built a "falling notes" style web interface that works with a midi keyboard. You can mark a split in the keyboard and just practice one side or the other. Most of the controls I've baked in use the keyboards other buttons (Novation Launchkey 61).

It's open source so feel free to adapt as needed.

https://benkaiser.github.io/learn-piano/

I've found it works well for my wife and I playing simple songs together, she never learned sheet music (and I'm not great at it) so this format is very easy to follow.