Might want to run down through the standard list by popularity and choose based on your needs: alternativeto.net/software/zoom-cloud-meetings/

Keep in mind Signal can do some conferencing too. So look at some of the real time communication tools tool at www.privacyguides.org/…/real-time-communication/ .

Thing about conferencing is a lot of the large conferencing tools are not that secure in terms of full end to end encryption and they generally need a lot of infrastructure to support a lot of people so there is a question of who runs it and who pays for it and who secures it.

I will be interested in what others say.