babymusic,
The concept of live arranger was asked over and over. I, myself asked for that quite a few times. There was a member on the forum that presented a working concept. The problem is - Real Tracks are not short MIDI snippets as Yamaha uses in their styles. They are long Audio performances and often there are better and less than better takes of same chord sequences. BIAB algorithm randomizes and glues together these performance "takes" when you generate a track. This is not a "live" process. To do an arranger each style has to be manually curated to pick out best parts so output is very consistent. Basically a giant Rompler with pitch & stretch capability. Overall, it is awesome idea that should definitely be explored by PGM, but it is a large uptake.

What is more realistic and close to your request, in view of absence of parts such as Intros, true fills, etc is this:
https://www.pgmusic.com/forums/ubbthreads.php?ubb=showflat&Number=882175#Post882175