I tested matrix in 2021 and found the experience pretty darn awful outside the main client. And by a cursory glance the ecosystem is still pretty much controlled by the matrix.org folks. When I was using it there was a lot of accusations that Synapse did not follow the specification and that server implementera had to reverse engineer what Synapse did to be able to federate.
And talking about that: does federation work properly yet? I used a third party provider and it made my life miserable.
I am all for federation, but in my experience the "federated" part of matrix was a lot worse than the jabber one they want to replace.
