There's cinny, which is a pretty polished Matrix client that is very, uh, inspired by Discord in its look, that might soon add voice rooms: https://github.com/cinnyapp/cinny/pull/2335

I played around with this implementation and it's looking pretty good. Not there yet, obviously, but we're in the ballpark I'd say. Obviously, there's lots more to Discord than just voice rooms and a similar-enough UI. But we're slowly getting there.