I'm a regular jitsi user.
jitsi is free software. I don't have the bandwidth to run it; otherwise I already would be doing so, instead of using other peoples' servers.
the free service is provided at https://meet.jit.si/
You pick a conversation name, such as
and everyone that connects to the URL is connected together.
There's no password or registration for their free servce. Just make sure your participants know the URL and the time they should join.
The jitsi site will suggest random names, but I suspect we'd be better off chooseing one we can remember easily. Such as the one I provided in my example.
I seem to remember a limit of about a hundred simultaneous users for the free service, but now it seems to be 25. (not sure about this, though).
If you don't want to use the free service, there are instructions how
to set up your own server on the site. Or you can pay them for larger meetings.
I've attended jitsi meetings with about tn particilants. I find it more convenient tha zoom.
It does seem to remember when I've had meetings on the public free kitsi server, so it's not completely anonymous. I do provide it with my name when I connect, for convnience. Some of us users don't, and are labelled as 'jitsi user' instead. For all I know, it may store cookies on my machine or remember my IP number. I have never told it my email address.
The Devuan developers have a weekly chat on jutsi, but we use our own server.
Service on the jitsi free server has usually been excellent, except once when the server seems to have been down. My meetings on it usually have about four or five participants, byt I've attended one with about eight. We'll have to try it and see..
I've never used BigBlueButton.
I have used discord for video chat lasting about three hours. I don't know what the limit is.
I have used facebook messenger for video chats lasting more than two hours, but with only two participants.