OceanPaddler,

In the long run I think you will end up making your own tracks.
The other approaches (free ones and purchased ones) will prove frustrating with their own problems.

For example,
Rarely do all levels and mixes work between a disparate set of backing tracks.
Rarely do 2 musicians agree on how loud the piano player should play.
Sometimes what sounds good in the studio sounds horrible at the gig.
I can't remember how many tunes I've remixed after playing them at a gig.

I have found that I can build a performance ready song with BIAB and my DAW (Logic) in about 2 hours. Sometimes more, sometimes less. 3-4 in a 8 hour day.

I am probably an intermediate level BIAB user. Certainly no expert.

This is for a fairly straight ahead song. A short intro, verses, chorus, room for some improv soloing, restate the melody, and an ending.
Maybe a hold or shot here and there, nothing fancy.

I set the arrangement, tempo, key & style inside BIAB. sometimes I spend a good bit of time auditioning various musicians. I use real styles only, not midi.
I export single file per musician wav file out and mix in my DAW. Sometimes I use a little automation for levels and add some tweaking. Then I use A LUFS meter to make sure the output level will be consistent for all my work. User Teunis on this forum educated me on this critical step of the process. Don't overlook it.

Yes, it is work. Don't know how to get around that.

biab2023(Mac)
Logic Pro X