Very good info.
During this pandemic, I've been trying to improve by learning to play the correct chord, rather than substituting easier to play chords. And I'm also experimenting with right hand fills and runs between the melody, another area that dramatically improves songs.
On arranger keyboard play, using left hand as a fill while also triggering chords takes a lot of practice, and I'm having a hard time getting it. Too many years of lazy left hand play I guess.
...It's hard to teach an old dog new tricks