Your feedback would mean alot to me. Building real-time tools for practicing is super important to me as a self-learner since it’s hard to both be expressive and technically sound, so I’d love to know if this is useful and what direction to take this.
This is common/usual, the traditional remedy is to practice with a metronome. (I did that for a while - well, come to think of it, I never stopped doing it!) So I guess you tried that and..it didn't work, or something?
Oh, I just noticed "I’ve been practicing without a piano teacher for several years now" which I assume means, you only started playing a few years ago. I wouldn't expect your control etc to be great after only a few years!
I'm not sure how much benefit this would be over a metronome - I mean, you can hear whether you're in time with a metronome or not..can't you?
The flow thing sounds weird, not sure what it is.."When you just want to jam with music you already know, use Flow to get new insights on your playing, so you can work on being more expressive." What genre(s) of music did you have in mind for this?
Ah, I felt bad about not downloading and trying it but now I see it's only for iOS, which I don't have :-)
p.s. If you have in mind not, say, solo classical piano, but music played with drums, like jazz/rock/pop - everyone has, or should have, their own sense of time, and I don't think trying to play exactly where a machine says is perfectly in time would always help with that. There is an overabundance of robotic players from music schools these days; we need more individuality, not less! Part of that is having your own sense of time feel.