I've narrowed the problem down to two things:

1) The bigger Wilderness map loading causes some major issue that crashes the game. The only workaround that I found to fix stuff for me is to restart my PC, don't turn anything on except BGIII, drop everything to very low then load. This usually works and the map loads. Then I can change the settings back to Ultra and I can play....

2)... but there's another thing - playing the game for 30-40 minutes on Ultra will inevitably crash the game. Also I just crashed on another cutscene in a particular dungeon after pressing one of the buttons in there, but I have no clue if the crash was due to playing for 30 minutes or the cutscene that triggered.

So my best guess is that the game has some sort of issue with CPU/RAM usage. I've got i7 7700 HQ and 16 GB of RAM, so there shouldn't be any problems, my load on both isn't very high when playing (around 30-60% on both). The game clearly can be handled by my laptop, but some sort of issue is maybe cause mishandling of RAM and this leads to the crash? It's pretty telling because if I use the PC for a bit, or already crashed, I cannot load Wilderness map anymore even when using very low settings.

I think that for me that might be the underlying issue, not some particular spot of the map or particular cinematic. Perhaps cinematics push the game resource usage higher than normal game play and this is why it crashes on them so often.