You should stop using Nostalgic glasses. How can a 20+ years game do something better than Larian?
Easily. BG3 looks very much like D:OS2, and D:OS2 UI and controls simply aren’t good enough for a party based RPG. Issues with their control system has been pointed out multiple times.
On another thread people pointed to KOTOR or Dragon Age as originators of this control scheme, and that’s right. And that control worked for those titles - except KOTOR and Dragon Age had no, or almost no environment interactions. Controlling single character, and having others blindly follow was fine for those games Larian uses a lot environment interaction, and control scheme they implimented is too clunky, too unreliable and too tedious to be good. I agree, that having a proper RTS controls would pretty much solve everything.
A simple test for a good UI is: how many clicks and how far I have to move my mouse cursor to get things done. In case of D:OS2 or BG3 the answer is: way too many clicks, and too much portrait dragging.