5e is a bad table top game, but that's part of what's made it so successful - it's not treated as a game unto itself anymore, but just some loose guidelines to help generate setpieces, and people like that.
But also BG3 seems to recognize this and actually fills in the broken or missing game elements, just like everyone's DM does whenever they come across these gaps. It takes an opinionated approach to implementing the rules, and does so with the confidence of years of building CRPGs.
It's an impressive feat.