i'm sure the OP has something in his head - and it's probably achievable in BIAB but it will take a little work. but getting that sound in BIAB courtesy of PG Music - who are not mind readers - at the touch if a button without making an effort is a a little too demanding.
Indeed.
So far I've mostly used BiaB for accompaniment whilst practicing at home. For that I type in the chords, pick a style that suits, generate and play, warts and all.
I'm now starting to put together works that might be releaseable, but there's almost no way I would expect BiaB to produce what I want, straight out-of-the-box. Indeed, whyever would I even want that? I want something that's special to me. I have numerous VST instruments that I think BiaB doesn't (Cora, Balaphon, Djembe, et al). I may graft some of those onto MIDI tracks, some I'll play via the keyboard, I'll expect to spend quite some time adding nuance, character, expression.
I like and rather aspire to MusicStudents tagline:
"...My goal is not to create backing tracks for my music, but rather to get more of me in my music."