Steam Workshop - No, not even when I still had games that I play there. Now I have almost all my games on GOG, so, even less.
Vortex - NO!
Bethesda games - MO2
Unity games - Either UMM or BepinEX
Larian games - their respective mod manager (BG3MM right now) + manual installation
CDPR games - manual installation
Plenty of mods out there already for BG3. Get BG3MM and go mod, instead of waiting for Steam Workshop that will pop who knows when.
Would it not be nice if ALL the game devs created a standardized Mod introduction system so we could have a single program for mod managing ANY game?