It can be a tiny bit involved to install but if you know your way around Linux already it’s perfectly doable. The arch wiki is a great reference for MANY things and it has a dedicated page with installation instructions.

I like that it’s lightweight because it comes with the bare minimum for a working Linux install and everything on top of that must be explicitly installed by you. I also love pacman (the package manager). It’s never borked anything for me and I’ve yet to be dropped into a dependency hell in 6+ years of using it.

I use matrix synapse. You can self host or join an existing server.