If you would prefer to self host, there's always FreeSWITCH [0]. It can act as a server for meetings. There is a webRTC client called Verto Communicator that seems to work quite well, or you can use SIP clients.

The documentation is a bit lacking, but it's actually a very capable system for unifying voice, video and chat communications – and a whole lot more.

[0] https://freeswitch.com/