If your business model is a subscription plan, you're putting yourself in a market with established competitors that have much higher quality (right now) software and content.

You really oughta do the math, consider how many subscribers you might be able to attain and how much to charge and whether that makes your ends meet.

You've probably already considered the licensing fees of the sheet music and/or background audio. Just getting into a discussion with the copyright holders is going to be an uphill battle when you're not the first mover in the field.

All the best to your project, I might give it a try later.