Matrix is a protocol for secure communications.

This blog post is a good overview of the problems with Discord and what you can use instead.

I personally like the Element Client for Matrix, but there are others.

Btw, if you still need to use discord, but want it to be less privacy invasive, apply a filters list in ublock. The devs got around ublock in a hacky way, but at least it’s somewhat easy to get around.

Trafotin’s video covers this pretty well.