How is installing a matrix client any different than installing an IRC client?
Meanwhile gomuks also exists and is usable and not abandoned.
On GUI Desktop, various clients are in active dev - e.g. Fractal for GTK/Rust, Quaternion for Qt/C++, Nheko for Qt/QML, etc. They are not as complete as Riot yet, but I'm sure PRs are welcome...
... although if I'm not mistaken, unfortunately none of them supports Single Sign-On yet, which is required for joining the Mozilla instance.
Also straight from the readme:
"Basic usage is possible, but expect bugs and missing features."
Not very promising.