@snow That is a good sollution but you need an e-mail which gives the metadata any way.
Look,
Not Tor-friendly: Cannot host a Matrix server as an onion service; Element web breaks under Tor Browser due to local storage wiping.
Metadata exposure: Your server knows user IPs and activity patterns unless behind Tor (not currently supported).
XMPP (with OMEMO) is simpler, uses fewer resources, and is more privacy-focused: you can use Tor on Wireguard SOCKS5 with proxied DNS e.g. and other obfuscation methods.
Minimal metadata leakage if configured properly as well.
For maximum privacy, XMPP is still preferred. Matrix excels in bridging and rich features, but not anonymity.
And I used it before I know it.
It's good though as normal messenger.
I want to stay positive, don't curse me these are facts and all do what he want

@snow Just my own taste is Session Messenger frankly and I used Matrix and Jabber before it was XMPP, a search result summary of which is best:

Session uses the Signal Protocol + onion routing, collects zero metadata, requires no phone number, and runs on a decentralized network (Lokinet). It’s ideal for high-privacy, anonymous communication.

XMPP is a federated, open protocol (like email) with OMEMO encryption (Signal Protocol). It supports self-hosting and full decentralization but servers can see metadata unless combined with Tor.

So for Self Hosting use that yes, for private messages use Session bro