This isn't necessarily a recommendation because I haven't really used it, but it appears as though the FOSS software called Tox (like "talks") might fit your requirements:
https://tox.chat/I think it is P2P, so it's kind of locally hosted, but definitely decentralized/distributed. And it's end-to-end encrypted, so that should alleviate any concerns about proprietary work stuff.
There's also an open-source Discord alternative called Stoat (previously called Revolt) that you can try, but again I haven't really used it other than installing it and tinkering with it for a few minutes (a few years ago):
https://stoat.chat/ 
