For what it’s worth I don’t think an app is the answer. I tried Yousician but I felt that just following the bouncing ball didn’t improve my ability to remember chord progressions etc. I just mindlessly followed the bouncing ball. Didn’t work for me.
I think learning easy songs from start to finish is where it’s at as far as working on lots of different skills ie timing, feel, dynamics etc. Play along to YouTube videos with rolling tab at the bottom. Completely free and improves your playing.
Then record yourself (just do it in your phone to start with)
Listening back to your playing is real tangible feedback.
The best thing for my playing since doing B2B has been learning whole songs.
Lots of fun easy songs to get you started. here’s a few suggestions: