Ditto. with ipad 7, no sound with 18.3 beta on any site or app (incl youtube app). so none on airpod/wired phone/ no external speakers attached either. the same os version 18.3 public beta - works fine on iPad 9 though.

Fortunately the latest 18.3 beta (22D5055b) has fixed this problem on the ipad 7th gen. Thanks to the Apple Engineering team for dealing with the matter in a relatively short time frame (but users of course felt like it was an entirety)