@SirTapTap Matrix is fairly cool, though it lacks some bells and whistles, and actually getting people to use it can be tricky.
They seem to be partially? based in the U.K., which has been overtaken by modern fascism (heck, not that long ago, U.K. MPs wanted to censor pictures of boats crossing the channel in order to be "tough on illegal migration"), and is Internet hostile, so probably self-hosting is best.