I don't think there's much you can do within Biab, since realtracks are just audio recordings, and if these major chords were originally recorded as dominant chords, you won't be able to change that.

However, you could try to use playable realtracks if you have that piano sound and you can emulate the rhythm later with midi, but I'm not really familiar with that feature, I experimented a bit when it was introduced and the result was not really good.

Another maybe better would be using Melodyne to edit the audio, which will allow you to remove those annoying 7ths from those chords.

BIAB 2024, latest build.