itch.io

Thank you SO MUCH. It worked! Just so everyone knows, use your distro's guide to install steam (be sure to uninstall your current version) and then follow the above steps. It should work.

Nope, same issue as ParticalMan but I'm using the pre-installed version of Steam that comes with the Steam Deck. The C++ framework never installs, nor does the Unreal4 prerequisites. This is true for every single game that I add to Steam and force Proton this way. Only games that don't require prerequisites actually work with this method for me.

Update: A year ago that was what happened when I tried this exact method. Tried it again just now to see if anything's changed and it inexplicably worked this time. Linux moment I guess?