Computer Configuration > Administrative Templates > Microsoft Edge
Both
HKLM\Software\Policies\Microsoft\Edge
Restricts the UDP port range used by WebRTC to a specified port interval (endpoints included). By configuring this policy, you specify the range of local UDP ports that WebRTC can use. If you don't configure this policy, or if you set it to an empty string or invalid port range, WebRTC can use any available local UDP port. Example value: 10000-11999