Teamspeak used to be the best. I used it for a decade. It's only within the last couple years as they've tried to become Discord that it's started going downhill. Teamspeak 3 was solid enough but soon they implemented the artificial lifetime, you had to re-authenticate your server every year (and sometimes more often). Then they got rid of the old forums and wiped everything clean. It hasn't been the same. I stopped using TS recently.

I do use matrix, but only because of the pandemic. And matrix itself only does 1-to-1 voice. For multiple it has a system to shunt you over to jitsi and autoconfigure the room. So I don't see how TS5 is going to use matrix.