The whole replace Discord thing is something I've been thinking about since 2019 and building my own IM platform since 2007. I hear people pitching every platform under the sun, but the one that I think has the most potential is XMPP. I've been building a modern client, nothing worth showing yet, but eventually I'll slap it on my blog and do a Show HN, for now it supports very basic XMPP primitives, adding friends, setting statuses, messaging friends, simple stuff.

Back in the late 2000s and early 2010s Google and Facebook supported XMPP, so you could login to Facebook Chat / Google Talk via Pidgin through an XMPP gateway (if if this was the default protocol or a bridge I'm not sure, its been years).

The biggest strength I see for XMPP is that because the web and even enterprise (think banking etc) uses XML too, everyone's optimized the ever living crud out of HTML so you could get some very high performance libraries to churn through all those stanzas, but also more importantly, its an extensible protocol. There's no reason it cannot have half of the things that exist on Discord, without disrupting the protocols OOTB design, because unlike IRC and other competing protocols, its extendable by design.