(Thankfully, you can use the launch command --skip-launcher to boot straight into the DX11 version of the game, or use --skip-launcher --vulkan to boot straight into Vulkan.)

And

In terms of overall recommendations then, I'd suggest DirectX 11 is a better choice than Vulkan for most users with Nvidia and AMD graphics cards, especially those with relatively modern CPUs that meet BG3's recommended specifications. While Vulkan did run better in static scenes when CPU-limited, its poorer performance than DX11 in NPC-rich areas is problematic, making DirectX 11 a better choice overall.

Looks like these guys say DirectX 11 is usually the better pick. I've been running Vulkan and the only negative I've seen is there is a large block that will flicker slightly on the right side of the screen in cinematics. I've going to try DirectX 11 and see if I get the same FPS and quality today. Vulkan with DLSS on quality I get around 100+ FPS. I have a Nvidia 3080TI and intel i7 12700KF.

Edit: I'm running the game on a 4k TV with 120hz. Looks great.