I’ve modified the @nazar-pc branch, allowing to listen to the same UDP port and use the STUN username to map the incoming UDP packets to the right WebRTC transport (taking some parts from Webrtc sfu UDP single port solution design · UniverseParticle/mediasoup@cbe5e57 · GitHub). More work is required to allow the cleanup of the listening socket objects when no more transports are using them.
To try it, you have only to modify the mediasoup-demo config.js adding the webRtcTransportOptions.port option. As it is, only a single worker configuration is supported (set numWorkers = 1).