Thank you @madhens and @gardotd426 :) The screenshots are really useful.
The AppImage for Gamebuntu has been replaced with a package in the MPR. Here’s how to install it using una: https://gitlab.com/rswat09/gamebuntu/-/blob/main/README.md
It will make the update process more streamlined as I package and upload more and more game-related tools to the MPR (which is basically the AUR for Debian and Ubuntu-based systems).