If in BG3, you were ONLY in control of your own character, I actually wouldn't mind it being completely Turn Based. But I LOATHE having to micromanage more than 1 character each turn. It's like when you are at an actual D&D game, and the other 3-5 players don't show up, but the GM hands you their character sheets and tells you to play their characters for them. It isn't fun, atleast not for me. I want to play ONE character, not everyone elses. RTWP games generally let me do that because of the AI that they usually come with.
Sounds to me that what you really want is AI for companions. There is no reason you couldn't have it in turn-based.