A:AnswerDepends on line of sight. If it's a clear line of site I've gotten as fast as 20ish feet and they still work. Once you add walls in between you won't be able to hear as much.
A:AnswerAt the current time it does not look like the airpods 4 will get the hearing aids update. Haering aid update is only currently available for Airpods Pro 2s.