It runs worse on DX11, was getting random periods of what felt like 30 fps or less roughly half the entire time I was in the versus basement after changing video settings. I swapped back to DX12 right after that.
Feel free to back your old user_settings.config up and you can replace it again after. It may be worth checking the issue with fresh setting first though, just in case.
i have tried everything backed up my user config disabled mods and everything it still happens on dx12, but for me its rather a peculiar issue that causes my mouse to hitch even outside of game after i play it for a bit. only happens in vermitnide not darktide.