I’ve been trying to use Matrix to replace sites like Discord or Slack. But it seems that if a user creates an invitation-only room in a server, then invited users who are registered on other servers get errors when trying to join. Not very useful error messages either: “Failed to join room”. (In my case, I tried creating accounts and rooms at nitro.chat and then at converser.eu, but friends registered at matrix.org don’t manage to join).
Quite a let-down. Anyone who’s facing the same problem and has maybe managed to solve it?
IRC can actually be quite good. The main problem is the super outdated popular networks like libera.chat, but if your run your own IRC server with modern clients it works nicely (or you can use a good bouncer like Soju). Supplement it with a Mumble or Jitsi-meet server and you got at least a functional equivalent to Discord, even though of course not nearly as polished or easy to use as Discord.
I run it off yunohost which comes with it by default. Im not saying its the best to have servers come with it by default, but I sure use it quite a bit!