So I did a couple more tests at various speeds and laser power, turns out the first run was really not far from optimal in terms of contrast.
However I kept getting the non uniform color in the large lasered surfaces (the “C” in the logo),
which upon closest inspection is a really interesting ringing pattern:
I reduced the accels from 400 to 50 and rerun the job, and got this:
which reminded me that I had already had this accel issue last year.
I guess my laser mount is not rigid enough, I’ll have to work on that. But for now, 50mm/s-2 accels it is during lasering.