Earlier quoted context omitted.
Is there a widely-used open modern chat network? Specifically, I'm fine with the feature set of IRC, but I want durable messages and a mobile client. Speaking as someone who hasn't run their own bouncer in 10+ years.
Yes, Matrix. It all seems a bit overengineered, but it's open and has good clients, and all the modern features you'd expect.
So far, I've only found clients with different bugs. Calling them good would be a stretch. Passable, perhaps. But the scene as a whole is more of a choose-the-bugs-to-live-with situation than choose-a-good-client.