For the record, BG3 has completely blown me away and I'm already a huge fan, and I'm only just finishing Act 1. This is my biggest criticism, but it's a relatively small thing.

So when you enter turn-based mode outside of combat, the environment has its own "turn" in the initiative order. But during regular combat, the environment continues while everyone in combat is "paused." Any reason they didn't do the same "environment turn" in combat? I think they sort of did (at the end of initiative is when fire spreads, for example).

For me, it's a bit immersion-breaking. For example, I sent my rogue to distract and lead away a large group of enemies, so the rest of my party could sneak past. But I didn't have to lead them far, because once they got a few steps away, I could switch to my other party members (who weren't in combat) and they easily snuck past the "paused" enemies. I know if they had been seen, they'd have joined initiative, but it was super easy to avoid that because the enemies were frozen in place, so avoiding sightlines was trivial.