It's pretty easy to host your own!

XMPP is really lightweight. Just be sure to run OMEMO extension on the server for encryption.

I tried a bunch of alternatives like Matrix, but did not like it. At all. I returned to XMPP. I run one for my friends and family. Server will run on a potato. Clients too. Supports inline images and video, presence. Tons of clients to pick. Every last OS has them.

It feels like how things were before the Great Enshittification.