It’s pretty fine until act 3 when the sheer amount of NPCs running around max out the CPU usage and drop the FPS down below 20 pretty much no matter what graphical settings you try to run as there is just no power left for the GPU.

OTOH, BG3 is a turn based game so low FPS isn’t an obstacle for playing it, it’s more of a visual nicety, like higher resolution or clearer textures, itself.