Agreed. I suggested Jitsi to a few university professors early in the pandemic last year. They used it for a good 6 months, with classes of about 20 people, 2-3 times a week.

The experience of not having to login and fuss with accounts was great. However, when everyone had their cameras on + screen sharing, audio quality typically suffered.

These professors since moved on to use Zoom and it’s way more stable. I don’t like Zoom generally (for many of the reasons noted in this thread), but it’s definitely reliable.

Galène[1], which is FLOSS, was specifically developed by the University of Paris for the purpose you're describing.

The UI is terrible, I'll admit that, but the performance and scalability is better than Zoom.

[1] https://galene.org/

This is basically trading one reliability issue for another. The one chosen by the professor is reliable in excluding some students, the ones who actually care about their privacy, from the conferences.