[lydian]

For me it was like riding a bike. I didn’t have re-learn anything, just picked up where I left off. It’s surprising all you prior knowledge is gone. So I don’t really know what to tell you besides start as a beginner. If your beginner books are too basic, get some intermediate books. But it depends your goals. For reading, then Rubank is fine. For improv and scales/patterns, just listen, transcribe and play. All scales/chords have simple patterns you can learn by ear. Then just play them until you can do it without thinking.