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.
Actually in my current run (on Balanced) I’ve found that I can’t really do that. If I group sneak towards enemies I can attack with one of my characters, they leave hiding to make the attack, and then typically get spotted and start combat (unless it’s from far enough away that they can re-hide and attack again before the target gets within sight). Then all the involved characters roll initiative, and my character that attacked doesn’t have an action for that turn. Any other members of my party that are hidden can still attack out of combat, but the same situation occurs; they leave hiding to make the attack, get spotted, roll initiative, and then when their turn comes around they don’t have an action (haven’t had the chance to see how this works with extra attack). This could probably be cheesed with super favourable terrain and some pre-planning, but I think at that point you’ve more or less set up an ambush and it’s ok to get some extra benefit out of that.
IMO this is a pretty good way to handle it within a video game context, because it limits the cheese while not totally removing player agency by possibly undoing your attack. Like you said it’s different to how that’s handled in tabletop, but as a DM I’m able to explain how initiative is literally a skill check to see how quick on the draw you are, so my players hopefully don’t feel as cheated if they want to attack first but can’t act before the enemy. I do enjoy how the player urge to get as many free attacks in as possible at the start of combat is the same in both games hahaha.