For me the performance increased when I switched to dx11, also my rtx 2080ti is 20c cooler when using dx11 instead of Vulkan.
Take it from a guy that has tried coding with/in Vulkan. It is NOT easy! It's gonna take some time to get that working correctly, so if you have a Windows-based PC, you're best off just using DX11. Vulkan won't be any faster because you aren't going to unload any of the DX11 drivers when you install the Vulkan versions, meaning you will have two drivers competing to control the one resource (your graphics/graphics card). Vulkan tries to access the video card directly, circumventing the OS, and Windows does not like it when you try to ignore it. I don't think there is a way to unload the DX11 drivers under Windows 10. I think you can do this under Windows 7, which *might*, maybe, help.
You're better off sticking with DX11 on a Windows machine. I know you probably think that DX11 is slow, or clunky, or {insert negative Microsoft comment here}, but, from what I could tell at the coding level, Vulkan and DX11 act relatively the same, meaning, again, two drivers arguing over one resource.
