I found I got less shakey lighting performance with Vulkun. 3070ti, for what it's worth.

Vulkun is technically superior, but, I believe those superior bits aren't used as vulkun support is just an alternative for the DX11 features used - none of vulkuns fancyness was added.

Edit: comparing vulkan to dx11, dx12 competes better but valheim is a dx11 game.