Text chat? Why do you want yet another one of these? I mostly clicked the question because I thought it would be about voice or video chat, which still have some gaps in the landscape. For text chat I'm basically happy with irc.

I do think there is a missing or hard to find piece for privacy oriented friends and family chat (i.e. for just a few users, not a large userbase like discord). It would among other things have a super simple desktop client that doesn't confuse my mom. Maybe an IRC extension would suffice for the server side. Client side would be tkinter and super simple, no menus, no channels, no configuration options, just type and leave it running. I sometimes think of writing something like that.