That's an interesting feature. I didn't know that audio technicians and scientists solved this problem. My father-in-law started wearing a hearing aid a year ago (before Biden made it easier so It had a hefty $4k price tag). It was hooked up to his phone. I don't think he was very savvy with the volume button. Often times he didn't know if the sound was coming thru bluetooth or the phone directly. Now he has a ringing problem that keeps him at night. And he needs a white noise maker to tone it down.

I will take a trip to the audiologist at Costco to get more insight. I hope it is as good as you say it is.