I'm certain that some Baldur's Gate 3 fans would love to only control your main character and let the AI handle your companions in combat. And there is now a mod that allows for such a thing.
I imagine it’s the same ai level that you play against the whole game so… some fights are brain dead and some fights I feel like I’m playing against a chess master
I'd say it's fairly good. It's so good, in fact, that when you leave it no good moves to make because you obliterated their strongest dude and then jumped 30 squares away in a single turn, it literally holds the game up for a solid minute or so trying to figure out what to do.
If the AI for the ghouls from Danse Macabre is any example, they make stupid choices. The ghouls can be standing next to an enemy and waste their turn with Dash to get to another enemy.