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)

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.