I loved using XMPP and used to run my own server and even had the apps that would send notifications from my phone for different events over XMPP (forgot the name at the moment).

I'm all-in on Matrix right now and use it for my family but it's a far cry from the usability that XMPP had. I am still hopeful that Matrix can live up to its promises but perhaps XMPP will always be around if that doesn't work out. Who knows!