There is still only one implementation of the Matrix homeserver protocol. Just one.
But hey, at least we have built-in VOIP and color unicode emojiis. You couldn't possibly have a successor to IRC without features like those. Glad the Matrix folks have their priorities straight.
The world has already tried decentralization without putting the average user's needs and wants first, it's called XMPP and it's there for you to use and call the echo server, if there even is one to respond. Matrix has a long way to go, but at least it hasn't given up before it started.
Our project https://snikket.org/ is using XMPP and has all the features you listed. My 85yo grandmother does in fact use it to video call her grandson, regularly :)
https://joinjabber.org/ has a handful of recommendations, and if you're curious about features supported by a specific server, check out https://compliance.conversations.im/ to view that information.
I can't speak for the backend, because I've never hosted a server myself, but I find the good XMPP clients to have many more features and to be much more performant than the good Matrix ones.