D&D is a party-based RPG. When you play D&D, do you play the whole party, or do you play ONE character within the party? This is the crux of my issue. Whether it is Turn-Based or RTWP, if the game is supposed to emulate D&D and use their ruleset, I only want the choice to only control one character (without playing lone wolf or multiplayer).
The players, collectively, play the whole party. BG3 is single-player, with the one player taking the place of the players (and arguably the DM, under some circumstances).
The BG games have always been party-based, with a single player playing an entire party. They are RPGs in the tradition of classic party-based CRPGs such as Wizardry, Ultima, and Might & Magic.