I mean, that's the entire issue. There's very little tangibly better than Discord. I like the idea of Matrix, but it's complete garbage in practice.
At least for now, the solution lies more in mass outrage and action rather than any technological migration. The post raises this and I think it's a good point.
The difference between XMPP group chats and Matrix group chats is that Matrix servers replicate all the message history, whereas XMPP group chats are hosted on a single server. IMO the "bring your own account to a central server" model of XMPP is a good thing, but the "replicate all the things" model of Matrix is not.
In recent days people have been coming out of the woodwork trying to join again.