Unrelated. Tried Matrix for the first time a few days ago. Horrible experience (very slow). It's a shame it's borderline useless, because it brought back nostalgia from my IRC days.
I value a federated open standard, but I'm not gonna be the one running it...
The android Element client has been sluggish too, but I believe most of the lagginess comes from the matrix.org instance. Matrix supporters seem to brush this off as "oh well, that's just the matrix.org server that's laggy, it's not a problem intrinsic to the protocol." It's the most important server that's borderline unusable!
Honestly I didn't find matrix to be much worse than Discord. I don't know what people are looking for in these kinds of apps but Discord might be the worst (maybe weirdest?) application I used willingly.
Matrix irc bridges are good as an irc bouncer I don't need to run myself and there are a few open source communities that chose matrix as their base. For what I use it for they are fine. My personel favorite in this space is Zulip.