I don't think it can be. Everything irc does is better done centralized. The big problem is leaking of user iP's. Ip's regardless of how they work technically are treated by police and courts as a unique identifier. As sad as it may be, Discord thrives far more than IRC ever did for that very good reason. All content has to be proxied, and that costs big bucks.

One way around it would be to stick to embedding of content only from a small number of known sites, but even then things like YouTube can still show geography of viewers iirc. Plus if those sites get tired of your bandwidth they can just block you, no negotiation of money if you don't have big bucks.

But regardless of how it's done, when you host your own actual server, you're now liable. You're identifiable, and In the U.S. identity is all that's required for any civil case, which could be thrown at you by anyone for any reason. When you host yourself you're taking on legal liability for your users, too, such as underage users that get access to pornography through it.