Maybe I just got unlucky but running an update today absolutely borked my Steam Deck running this build. Been running it smooth for a few months now, but after updating today I couldn't launch anything in game mode, proton or native. Worked fine in desktop mode, and if I let things sit for 5+ minutes in game mode they'd eventually launch sometimes. Spent a few hours trying to fix it until I just said fuck it, wiped the thing, and went back to SteamOS.

I swear by CachyOS for my desktop, but the handheld edition has given me more trouble than is worth, at least on the deck.

Edit: Opted for a fresh install before totally giving up and it seems to be fine now. Very bizarre but that's just how it goes sometimes

Edit edit: Nope, happening again. Seemed to work out of the box, but after customizing a bit and installing a bunch of junk in desktop mode, it seems to be doing the exact same thing again. Figured it might be Decky Loader, but it still keeps happening with Decky uninstalled (tested before the wipe too). No idea, might see if I can try a different gamescope-session package

Triple edit: Figured it out. The new gamescope session package doesn't play nice with Steam's Background Recording feature. Turning recording off completely fixed this for the time being.