Try out Snikket. Really easy to set up, with sensible defaults. You just docker compose up and have a pretty funcional XMPP server without needing to configure

Try out Snikket. Really easy to set up, with sensible defaults. You just docker compose up and have a pretty funcional XMPP server without needing to configure much. Adding complex things such as gateways onto Snikket is a bit more complicated, as you have to deal with Docker volumes etc to put the right file in the right place, but I found it easy to manage. I've been running my Snikket instance with gateways for WhatsApp and Matrix for a couple of years now and I'm really happy. It's very low maintenance