I’m running continuwuity, and ejabberd as text-only IM servers to talk to some communities. The latter (and XMPP in general) has more moving parts (more ports, SRV records, etc) to set up, but messages deliver much faster and take much less resources. They’d probably both run fine on a VPS with the proper tweaks anyhow - the Rust-based server makes Matrix actually not suck after all

For bridges, I’ve used maunium-discord as a Matrix bridge in the past, and trying out slidcord right now. I think Matrix bridges still got better UI/UX due to more supported features (spaces/threads) and coherent clients, though let it be known Slidge is a hobbyist project. If your chat server is mainly for bridges, stick to Matrix and consider disabling federation. Also Matrix if you’d like your friends to switch over from Discord - it has more Discordesque features like custom emojis/stickers and SFU-backed group calls

Though this doesn’t mean I’m unrecommending XMPP. I do appreciate its clients’ snappiness, in-band notifications, the general ephemerality of its chats, and unrivaled efficiency. I kinda wanna write a blogpost comparing both software and protocols, but right now I don’t have an opinion about one over the other. They’re both cool albeit they both leak different metadata differently

It’s basically XMPP with a clear packaging, from server to client