Not a big issue for me since the option is given to choose between DX11 and Vulkan anyway, and I'm not having the issues below in DX11, but still worth a mention.

There have been other posts on this forum a few months ago about Vulkan resulting in blurry images in 4k. I believe that is because the "4k" option in the display resolution actually sets the native resolution to 1440p, resulting in a blurry upscaled image, as all upscales tend to be without DLSS/FSR.

I play with the MSI Afterburner overlay to monitor fps + temps, and the overlay is significantly bigger when playing on Vulkan 4k vs DX 4k (a higher resolution should result in a smaller overlay). When switching DX to 1440p, the overlay has the same size as the Vulkan 4k overlay, prompting me to believe that Vulkan is displaying "4k" as 1440p.

I've had this issue from the start and haven't found a fix, and haven't seen this issue addressed in any BG3 news or update from Larian lately. I'm confident this will be fixed eventually, and again, not a huge concern given the alternative with DX11, but Vulkan usually performs better on every other game I play on my rig, so thought I would bring this up (again).