I've got a 4070ti running most recent nvidia-open on arch and haven't had that happen, but I don't tend to run with vsync often.
What proton version are you running this on? Had some weird almost microstutters in cutscenes playing DA:Veilguard through moonlight on my steamdeck. Swapping to experimental resolved that, think it was one version of proton-ge that I had the issue with.
Do you have vrr enabled by any chance?
Are you running through gamescope? Have had grief with gamescope and nvidia, but that was mostly with hdr.