My brother, XMPP existed before Web 2.0 where after the cost-cutting way to ship an app was a browser option (browser options help accessibility tho)—where Electron was the most egregious RAM stealer. OMEMO has been around for multi-client double ratchet e2ee since 2015. An ejabberd server can be tuned to handle 2 million simultaneous connects—Synapse folds over like lawnchair at a single user joining a room with a medium-length history.