It's not really convincing what you're saying as Apple have much more money/technology/people then literally any professional hearing aid manufacturer. Just combine total market cap and revenue and it will be in single digits compared to Apple (Oticon parent company Demant is just ~2 billion - Oticon probably way less than that). I would like to see spec sheet of mild hearing loss hearing aid of any of the manufacturers that are charging 10 times more than Apple and see how that hardware is different from what Apple have in AirPods Pro 2. Is there any exact sample you want to share? I really want to see actual spec sheet and see type of hardware they are using as it's complete mystery...

You are underestimating number of people working on them and data that is flowing into Apple from all the people using them for years.