I'll go against what most comments said and recommend DirectX 11. Yes, DXVK will translate it to Vulkan anyway, but Larian's own Vulkan implementation is definitely less stable compared to DX11.

I've experienced multiple crashes during simple things like opening the character sheets using the tab key, or crafting alchemy potions. I never had a single crash using DX11. I used Fedora 39/40 and openSUSE Tumbleweed, so the kernels were fairly recent. Radeon 7800 XT GPU.

I had the same experience under Windows 10 (before I switched to Linux), Vulkan has smoother frametimes but DX11 is more stable.

YMMV, this is just my experience from almost 400 hours played so far.

Always is better to use vulkan!

Dxvk is usually better, but using vulkan is the better strategic move, you'll increase their vulkan stats and provide QA. Good native vulkan support will beat dxvk every time.

DirectX is a Windows thing, so you'll just have those calls translated to Vulkan under the hood (DXVK). You'll probably get better performance from just setting it to Vulkan directly.

Edit: As some others say, for BG3 specifically, DXVK does a really good job. My personal experience is that "the best" option is very patch dependent. At launch Vulkan was best, then after a few patches did DXVK ran better, but personally I'm back to straight Vulkan, for no other reason than wanting to be a +1 in the statistics.