Since using gtx 1000 series it does have significant bug on wayland, i switch to xfce completely and rely on x11 worked fine lag free gaming, And Stick to Steam Proton Experimental because it offers newer version, What linux distro did you use ?
It also happens on X11 and Wayland (tested on KDE Wayland and dwm (X11)).
Anyway seems to be fixed now at least on Wayland (not sure what it was or if it was even related to Proton but happy it's fixed anyway). Will edit in distro and kernel to original post just in case it helps someone further down the line and will close the issue.
proton experimentalx1 2025-07proton 9.0-4fx1 2025-07
Proton version: proton-9.0-4f (also happens with Proton 10 and Proton GE)
Games tested: Watch_Dogs, Watch_Dogs 2, Tom Clancy's Ghost Recon Wildlands (not on Steam)
Distribution: Arch Linux
Kernel: 6.15.7-zen1-1
CPU: Intel i7 7700K
GPU: NVIDIA GeForce GTX 1080 Ti
GPU Driver Version: 575.64.03
Whenever I try to open Ubisoft Connect, it will either crash or start to severely lag my desktop session and I will generally have to ssh in to kill it (I can't switch tty) and sometimes I have to resort to SysRq to reboot etc.. It only seems to happen on the main Ubisoft Connect window and not the window showing something is updating or a game is launching.
If it is lagging but not crashing, then sometimes it will eventually stop lagging and it will be usable without issue. Sometimes it does eventually crash though.
This crash/lagging doesn't happen on normal Wine, only on Proton. It also happens on X11 and Wayland (tested on KDE Wayland and dwm (X11)).
There's some output about vkd3d in the logs generated by Proton so not sure if that has anything to do with it. This is only generated if it doesn't crash though, only when it lags.
Proton log file