I think Matrix let you connect to IRC, I don’t know if it had its own seperate chat though - most voice chat programs have.
Matrix isn’t really on my list of “things to try out” since I’m not really someone who likes to talk to people I don’t know (irl), especially in a language I have issues not understanding everything, mainly if people have either strong accents or speak very fast.
edit:
In its functionality, IRC is pure as it can get (don’t count DDC) and for basic chatting a lot of web clients are available. Most distros even have an IRC client installed by default or available in their standard repos. With most IRC networks having services (be it anope, atheme or others) moderation is definitely manageable (and rather easy) if you know some basic stuff about channel modes.
Also, our “original chat” was also IRC, and I just like it.
If discord is gone in 5 or 20 years, we can still set up an IRC server with all the channels 