WebRTC is end-to-end encrypted by default. There is a signaling server that helps establishing the connections between users in a room, but after that the communication is encrypted. Also those TURN and STUN servers are only required for technical reasons to get peer-to-peer working. So no content is ever passed unencrypted.
That's the difference to other services like Zoom and Jitsi, where a server in the middle is receiving the video streams unencrypted and then redistributes. Although Jitsi is adding encryption support for that as well soon.
