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.

So do I. During lockdown a french hosting company set up bbb instances on their infrastructure, and the experience was really good (they even activated the "join with your phone" feature).
Zoom and Gmeet are usable (usually calls are stable and quality is ok) but closed-source shit, and I had a lot of stability issues on public jitsi instances (though I never self-hosted).

I've tried opentalk for the first time a few weeks ago (it's included in my email provider plan) and it worked fine.