I haven't had much occasion to use it (I dipped into a gaming group that used Matrix but quickly fell out of it) but https://github.com/poljar/weechat-matrix seems mostly adequate if you are a weechat user and just need the text chat features. Feels just like IRC.

Many options here: https://matrix.org/clients/

Seems to be more on the "glossy" and "web client" end of the spectrum in general but probably there is some reasonable compromise to be reached from the proliferation of different clients.