After hosting Matrix for eight years, I've largely given up on it. It is resource intensive, slow and always seemed unreliable.
I actually got into hosting XMPP because of that, as I really wanted something decentralised that works well.
Here's a flyer from the Digital Independence Day (that was recently proclaimed by the Chaos Computer Club and a lot of other organisations in Germany) that shows two simple ways you can start using it:
English: https://shop.digitalcourage.de/files/xmpp-folder-engl-druck.pdf
German: https://shop.digitalcourage.de/files/xmpp-folder-Druck.pdf
French: https://shop.digitalcourage.de/files/xmpp-folder-F-druck.pdf
If any server goes down, I will not have much of an issue, as long as it is not mine. If it is a server my contacts use, I will only lose contact to a couple people, until those have access again.
It's a very resilient network and that's why I enjoy using it. It uses the same cryptography as Signal, the adaptation is called OMEMO.
Also, the clients run even on old phones, as they do not need a lot of resources, which helps when people have little money and also saves the environment.
It's reliable and just works, I like those qualities in software.