Yes Conversations is still a paid app on Play Store. The F-Droid version also doesn’t support Google cloud notifications so some message notifications will go missing occasionally. For Android there’s also Quickly which is a Conversations fork and aTalk which works OK but reminds me of 90s Windows software. It’s still quite usable though. Honestly Conversations is totally worth the money if only for the amount of effort gone into modernising the platform which also a testament to its extensibility.

It’s trivial to self host. I’m running a server on a small VPS for the family. Best part is they don’t even know they are running XMPP, just installed Conversations and that was it.