I suggest putting a good compressor with a make up gain slider or knob. Most compressors even out the mix, and that in general lowers the overall volume slightly. Having a make up gain post fader with allow you to raise the volume without adding more compression.

A lot has to do with what the tracks are for. If you are mixing to stay in BiaB to play there or if moving to a DAW the fix can be done there more efficiently.

You also may open the audio edit window and see if you can raise the gain on the bass track there.

Just floating some ideas out there.

HP Win 11 12 gig ram, Mac mini with 16 gig of ram, BiaB 2025, Realband, Reaper 7, Harrison Mixbus 9 32c , Melodyne 5 editor, Presonus Audiobox 1818VSL, Presonus control app.