For the windows .msi version, you might try installing it on a windows computer and then copy the install directory over to the deck. Then you can add the executable to steam as a non-steam game, and force proton through the “force compatibility tool” menu.

I believe the libXrandr.so.2 library can normally be installed on Arch by installing the libxrandr package, but I’m not sure how to install that on SteamOS without unlocking the filesystem.