Jitsi Meet is pretty good for video, and relatively easy to self-host, though you'll need some decent resources for it. The docker-jitsi-meet project[0] can get you started quickly
Signal's "source available" infra can be self-hosted but it's huge effort and relies on a bunch of cloud-specific services which need to be replaced with self-hostslable alternatives. It's also extremely poorly documented and the code quality is fairly mediocre. I wouldn't recommend trying to host Signal infra yourself; it can be done; I've done it at work and it took some months of effort, and maintaining it is a nightmare (or was, then at least) because they'd only push one huge update to GitHub quarterly or less often.
keybase.io has been great, although it's not without its risks either since it was acquired by Zoom. It's still up and seemingly maintained but AFAIK there's no new feature work.
I've heard WhatsApp recommended from people I trust, but I have never personally used it so can't speak from experience.
The legal team at the company I work for are suggesting to remove keybase and treat it as compromised as there is no way of knowing of keys and other data has not been shared with the Chinese government. No proof at all of course, just the world we live in I guess :)