Noting that Final Fantasy XIII-2 seems to suffer from the exact same issue. It reproduces when alt-tabbing while you have the escape exit "pause menu" up
proton-cachyos-11 with PROTON_ENABLE_WAYLAND=1 WAYLANDDRV_FOCUS_LOSS=0 helped me
PROTON_ENABLE_WAYLAND=1x1 2026-08
When alt-tabbing in Shift 2 Unleashed the first time you do it the game window will turn in to a small renderer in the top left corner of the screen while the rest is black. You can still see it working though. Upon a second alt-tab it will stay the same but with the visuals also no longer updating.
Screenshot
Software information
Shift 2 Unleashed
Fullscreen
System information
Apitrace file(s)
https://drive.proton.me/urls/C9P02R3AV4#pFLRNFmoD0p7
One with wined3d and one with dxvk where i alt-tab twice. dxvk is captured with
d3d9.deviceLossOnFocusLoss = Trueset.Log files
SHIFT2U_d3d9.log
SHIFT2U_dxgi.log