IRC could work as a backend for text chat, Twitch based their chat system on that and heavily modified things. Jitsi, or Jami support video out of the box. Could probably also roll your own with XMPP and WebRTC

You can run your own relays, the obstacle is that each relay takes up many terabytes. But it’s fully open.

https://github.com/bluesky-social/pds

https://whtwnd.com/bnewbold.net/entries/Notes on Running a Full-Network atproto Relay (July 2024)

https://news.ycombinator.com/item?id=42094369

https://docs.bsky.app/docs/advanced-guides/firehose

https://docs.bsky.app/docs/advanced-guides/federation-architecture#relay

TinyLLM on a separate computer with 64GB RAM and a 12-core AMD Ryzen 5 5500GT, using the rocket-3b.Q5_K_M.gguf model, runs very quickly. Most of the RAM is used up by other programs I run on it, the LLM doesn’t take the lion’s share. I used to self host on just my laptop (5+ year old Thinkpad with upgraded RAM) and it ran OK with a few models but after a few months saved up for building a rig just for that kind of stuff to improve performance. All CPU, not using GPU, even if it would be faster, since I was curious if CPU-only would be usable, which it is. I also use the LLama-2 7b model or the 13b version, the 7b model ran slow on my laptop but runs at a decent speed on a larger rig. The less billions of parameters, the more goofy they get. Rocket-3b is great for quickly getting an idea of things, not great for copy-pasters. LLama 7b or 13b is a little better for handing you almost-exactly-correct answers for things. I think those models are meant for programming, but sometimes I ask them general life questions or vent to them and they receive it well and offer OK advice. I hope this info is helpful :)