Thanks for the pointer. Forcing X11 fallback gets it to run on latest. I have got to move off sway. Needed to for years, this is just more reasons.

I click play in Steam, the button goes to "Stop" for a few seconds before the "unexpected error occurred" window displays. This is before any mods attempt to load, and before I pick a save game.

Arch linux, using sway. This crashed after updating all system packages to latest as of 2026-01-18 ...