I'm done with this now. Pretty much figured out the problem ... BIAB can't handle any chord length smaller than one beat with musicxml and causes placement issues which push other chords into the next bar, or misses chords out etc. You cannot even export from Biab and then load it back again where "microchords" are concerned. Open the same exported XML in Notion and it's still problematic. Stick with chords no shorter than single beat 1/4 notes and all is fine.

XML export from SMP works as it should, including 1/8th note chord durations, opens and displays the chords in the correct bar locations in Notion.

SMP chords to text, on the other hand, don't. 8th length chords export in an inconsistent way to a text file, which makes regex or even coded conversion impossible in some cases, so not worth the effort.

Best bet here is to do what I said earlier, double the tempo in SMP and then half it in BIAB. The other option is go through the chords in SMP and remove the short duration chords before exporting to XML and then manually re-enter them in BIAB. They are generally quite few so this shouldn't be too difficult either.

That's a cool sounding song in that video, amazing if it is AI. I did load it into SMP and got similar to your chords but not exactly the same which was interesting. I also assume you changed the pitch / key to Cm from Am.