Been several months since I played, though I did get and did play the update with the builtin turn-based mode (this is important, I'll get to it). Since the last time I played, I've upgraded my OS (on this 2017 iMac) to Big Sur. Last few days, I've tried, but every time I start Kingmaker, it gets to the Pathfinder splash screen and crashes when the progress bar gets to about the 2/3 done point. The reason the turn-based thing is important is that I had installed Unity mod manager and the turn based mode shortly after I first got the game. When the built in turn based mode became available, I just turned off the mod.

So, question: is it likely the mod (or the mod manager) is causing these crashes? If so, how do I get rid of it if I can't load at least to the mod manager screen? If it's not the mod or the mod manager, what could it be and more importantly, how do I fix it?

I had the same problem on Mojave, and it was in fact the mods and mod manager that caused it. Cleared right up when I uninstalled. This game does not like being modded on a mac.

You should just be able to delete the mods from the game's directory. That's what I did.

Same problem here. I got the game but seens not to be working on BigSur with M1 Macbook. I think will need a patch for it.