they use https://github.com/meetecho/janus-gateway as the webrtc backend, at least according to https://opentalk.eu/en/open-source-code-und-community. so the rust part is probably just for chat and signaling.
I really wish Jitsi had taken off during lockdowns. MS Teams I can understand, businesses all use Microsoft, but Zoom is just vile shite.
BBB (Big Blue Button, for those unfamiliar) seems to be the favorite of lots of institutions in Germany. I think a government agency recommended its use, that’s why it’s so widespread.
Jitsi has done a lot to improve functionality since lock down. Still pretty basic, but it’s free and can do moderation.