Why implement Fly at all if it's just another Jump?
It is jump with longer reach, and doesn’t consume bonus actions (do flying enemies ignore surfaces like in D:OS2?). It has value. Not sure if it is something I will be using, but I can see myself using it. It might not be an ideal implementation, but it is an implementation. Outside Solasta, I can’t think of any other top down RPG that could do it better.