Part of our large experience is also building video conference systems for both web and mobile apps within React and React Native systems. The main tech is reliant on the WebRTC and either building a peer 2 peer WebRTC system, or custom system relying on Kurento and leveraging TURN/STUN systems.
Outside of custom, we have also built systems relying on Agora SDK, Twillio Programmable Video or OpenVidu.