GTA V story mode was an excellent game, but it’s hard to realistically say a game from one genre is better than another, apples and oranges and all that.

GTA V’s online multiplayer, however, at this point is such a shitstain that I think it alone is enough to make the distinction clear.

It is. But only in so far as the content and scope of the game far surpasses anything a smaller developer could ever hope to accomplish. You may prefer one over the other, totally fine, but objectively speaking you get way more out of gta 5 content and scope wise than bg3.

As others point out gta online is a dumpster fire but it’s still massive and allows you to do endless amounts of things, racing, heists, owning property, running businesses, etc.