It only “leaks” your ip if you are trying to use webrtc features with a vpn, otherwise web rtc is perfectly fine to use without concern for most people.
"Keep in mind that this feature is to prevent leakage of your non-internet-facing IP adresses. The purpose of this feature is not to hide your current internet-facing IP address -- so be cautious to not misinterpret the results of some WebRTC-local-IP-address-leakage tests found online."
That said, my Firefox 91 and Safari don't leak local IPs regardless of the ublock setting.
Warrants more investigation perhaps.
https://bugs.chromium.org/p/chromium/issues/detail?id=878465
[1] https://datatracker.ietf.org/doc/html/draft-mdns-ice-candida...