[kingrolo]

You might like Scaler 2 https://www.scalerplugin.com/

It isn't really for learning theory but more for wielding it to write chords.

I use it as a VST in Ableton but you can use it standalone.

I also started learning piano as an adult around 6 years ago and have mostly been trying to use it to understand the theory to compose and improvise rather than perform. The more theory I learnt the more bits of Scaler made sense and I think half recognising concepts from Scaler as my piano teacher was explaining them at the piano was a help.

Also one other thing that I want to stress as I see it - some of theory is based on fundamental truths to do with clashing frequencies but also some of it is just trying to put a framework around what we already know sounds good, and the ultimate rule for music I think is, if it sounds good, it is good. Good luck!