And there is already a mod that replaces Nvidia Frame Generation with FSR3 in games like Cyberpunk 2077, The Witcher 3 and others: https://github.com/Nukem9/dlssg-to-fsr3/releases

Has anyone gotten this to work in Linux/Proton?

I guess that’s a bit better than the original command in question. But from what I understand it’s still unnecessary and there is simply no need to force the refresh. A regular pacman -Syu is all you need and will refresh all databases that need it.

You could install the linux-lts kernel alongside the one you have already installed to have the option to just boot into that one when a kernel update seems to be the problem.

Another thing would be to look into backup solutions that execute automatically when updating your system. Personally I have my system on BTRFS subvolumes and a package called snapper to manage the snapshots (backups). Alternatively the package timeshift gets mentioned a lot when discussing backup solutions.

Otherwise you did exactly what I have done to fix almost every issue I ever had. Downgrading the likely culprit and updating again a bit later.