Creatove Freedom Summit (https://creativefreedomsummit.com/) are doing their events with Jitsi, seems to be working fine. Other options would be Nextcloud Talk where someone recently told me they're using it in a university setting with lots of people and BigBlueButton which is also used by universities.
We tried to host it ourselves to save cost, and it's a beast but it mostly works. It certainly lags behind in features and uses a lot of resources, but when you compare with the cost it's certainly passable.
It's probably the best one when it comes to web-based videocalls.
I had much better experience with native apps (e.g. Mumble) when it comes to sound quality though.
Given a choice between Cost and Stable, if you have to prioritize one, which is It?
Then we're going to compare the others against each other. Then we're going to add in security of the stream. Then logging. Then privacy. Then security of the auth. Then suggest federation. Then interoperability with other media like POTS. Then anonymity. Then spam resistance. Then identity/trust assurance. Then your OS preference, server and client. Then onPrem (or private cloud) vs public cloud. Then apps vs appliances vs containers. Then C vs Java vs Rust vs perl.
I used to be a fan, unless I was doing something wrong on the website, you can only log in with proprietary software like github. You used to be able to just create a room. I realize that presents its own problems, but email should be an option.