Let's have the Fractal Matrix client available on the Librem 5! :) Here are the sources: https://gitlab.gnome.org/GNOME/fractal.
Is anything blocking that? That would be great to have it especially as they are working on supporting encryption.
I don't think it's feasible to package Fractal for amber-phone; however, it should be possible to have it in byzantium. Mobian has a preliminary packaging at https://gitlab.com/mobian1/packages/fractal