Hey honkycat,
I'm currently trying to solve the exact same problem you're describing, since I also got frustrated by the current state of music teaching.
I'm still in an early stage of development, currently trying to fetch proofs of interests and working on a prototype, but I should be able to release a MVP by the end of the year.
If you want to have a chat about it, or want to be on the list for early access, feel free to reach me.