It may be practical to just set up a server for yourself, as it tends to be lower-maintenance running a Prosody or ejabberd server, which usually has minor updates once every few +6 months or so (and typically nothing critical, like severe security issues). I should probably get around to updating/finishing my guide ( https://arcanican.is/guides/prosody.php ), since pulling in external repo shouldn't be as needed now (in Debian 12, soon Ubuntu 24.04, Fedora 39, etc)
In so far, I don't know of many fedi-adjacent XMPP servers (other than a handful neighbor servers that are predominantly 'furry' tilt, which I assume might not be an adequate fit).
For clients, it's generally 'Conversations' for Android users, Monal IM for iOS users, Gajim for desktop (with Dino as a newer option), and Movim (but I recommend self-hosting it, since it holds your login info on the server, most of the logic is server-side) for a Progresive Web App