Sorry, networking isn't my specialization, and I never read a book on those topics. (I know vaguely what they are and a little about how they work, but not enough to reimplement any of them on my own.) But many of those projects are open-source, so you can see the discussions (and code) about how they were built.

IMHO: I think maybe you're overthinking this a bit though...? If your end goal is just to have a place where people discuss primarily (or exclusively) over text, then all you really need is a web app that enforces that, like HN does. You can probably find some HN clone or reddit clone software and just use that, or Discourse (the forum, not Discord the chat app), and remove any multimedia functionality they might have. Or host your own IRC or Usenet server and don't allow images.

I don't think this is really a technical issue to solve, but a cultural one. Such places aren't common/popular because "I never want to see an image" isn't a big priority to most people. It'll be hard to get traction on such a forum, no matter how you build it under the hood.