That video is not out yet, or am I missing something?

https://www.youtube.com/post/UgkxJH41xfgExAQbc1ej3AkWVqSVjeR93WFf

Currently latest post, no idea how to link to that directly

Oh man, I want that source!

Not quite sure what kind of privacy you need, but matrix is reasonably easy to self host, and allows you to federate if you want.

Also has plenty of clients.

If you want low tech, hosting IRC is easy too.

They are currently adding calendar support, which is the most feature for me. We are looking for work it’s integration.

Now I am intrigued. Where on that line would you place nix?