No discussion on voice/video channels?

... this might be my aversion to video calls showing up as a bit of a bias. My hobby communities have been having the Discord migration discussion as well, but we don't tend to use video or voice chats at all, so it wasn't at the top of my mind.

Zulip has a Jitsi integration that allows one to start a Jitsi call via a configured server directly from a Zulip chat. Matrix has native VoIP, although one has to configure an appropriate STUN server and client support is limited. There's also an XMPP extension for voice and video calls, but client support is a problem there too.