Hi Bachus,
I had a look at Playground Sessions a few years back . At that stage I don’t think it was an app, it was online lessons. unless they coincidentally happen to have the same name.
The only thing that put me off is, they charged a monthly fee, but they also charged for the sheet music used. Gather things may have changed. I also checked out another site at the time, called, Piano with Willie. I really enjoyed watching his lessons , they were more based on Jazz and Standards.
Never ended up doing either. New Korg arrived on the scene, piano thoughts went out the window.
Wish I’d gone ahead now, especially the piano with Willie course.

One good thing you have with the app, is the real-time feedback ie if you’re improving and doing it right.
Apparently I can send stuff into my teaches and they’ll check to see if right or wrong, but it’s more complicated to get any feedback.