Neither of those thing are local-first, e.g. you can't search or compose messages while offline. Then again chat apps hold little interest when offline.

Chat apps like Discord hold valuable content and having it offline searchable would be really nice. Also, replying offline.

I think Matrix is getting peer-to-peer delivery so that will require offline composing, I think. I'm with you on search!

Nah, IRC and XMPP MUC

Both are beaten by matrix now.

In what way? Not in mature stable clients or in system resources for hosting a server. There’s issues around the centralization of Matrix.org and I've seen many cases where folks spun up then spun down a Matrix server 'cause it costs too much to run. In the case of Disroot, the closed their server to open an XMPP server instead.

https://disroot.org/de/blog/matrix-closure

you’re running on 2018 vintage data. plus there is no centralisation on matrix.org (beyond it being the biggest server), as has been pretty obvious in the situations where matrix.org has gone offline.