I have had only bad experience with its federation and chat clients over many years, I don't think it can improve, if it could, they probably would have fixed it a long time ago. Maybe not a popular opinion, but they should let the Matrix die altogether so something better can replace it.
Like... XMPP ? IETF standard, massivelly used (video-games https://xmpp.org/uses/gaming/ , IM https://xmpp.org/uses/instant-messaging/ , social...), modern features, managed by a fundation with a good ecosystem and plenty of alive projects: https://xmpp.org/software/ . Yes its not perfect, yes there's still things to improve, but the clients are there, working, on many platforms. The server-S (yes several of them!) a…
Anyone telling me "actually nvm, I'm switching from Matrix to XMPP again" won't get me to replace the chat app that I keep just for this one person plus 2-3 others with another experimental, broken, soon to be replaced chat app, they'll get a link to Signal and an invite to send me a letter if they don't want to use that.
Matrix seems reasonably usable for 1:1 channels at least, and I've also successfully used it for groups, including ones bridged to discord and IRC.