So, for a university project I had to use Unity. My OS is an Arch-based distro and wanted to use an AppImage for this. Then, realized that Unity discontinued the official AppImage at the beginning of this year (2022) in favor of Debian and RPM packages and everyone was angry, so I decided to make my own. I found a wonderful piece of software called pkg2appimage which creates AppImages from deb packages. Very convenient, isn’t it? In combination with Gitlab CI, I managed to automate the creation of AppImages through pipelines.
Note that I’ve only tested them with my host OS, don’t know about other distros. If you find any issue specific to the AppImage, you can report it in the issue tracker to see if there’s something we can do to solve it. I’d be grateful if you can give me some feedback here in this thread, like how it works for you in your distro, etc.
For desktop integration (specially needed for URI handlers used to log in), I recommend you to use the appimaged daemon from go-appimage and install the AppImage inside, for example, ~/Applications
TL;DR: I’m building up to date UnityHub AppImages which you can get here