BG3 is going to being in the DOS2 crowd and a lot of others who never played just because it's D&D, so I would think that alone will greatly expand their audience.
The only crowd Larian appears to be truly interested in catering to is the D:OS fanbase. Of course they will be happy to have any additional customers, and of course there will be some TT D&D fans who will at least check out the game, but D:OS fans are the core target audience the game is being made for and not for anyone who is not a D:OS fan.
