IPhone and ReSound Hearing Aid Conflict

A few months ago people I was on calls with said they could either barely hear me or couldn’t hear me at all. I took my Iphone Pro15 Max to a shop that fixes smart phone problems. The technician said the microphone was bad and replaced it. Still had problem but figured out that I could be heard fine by switching to speaker phone. Took phone to a certified Apple service center They recommended buying a new phone. Which I did, a restored Pro 15 Max. Had exactly the same problem, so I went to an Apple Specialist at Best Buy. She researched the problem and the next day, after some testing, concluded that the problem is conflict with the phone and ReSound hearing aid, but had no suggestion for a fix. At the community forum, lo and behold, another user described exactly the same problem with her phone that I am having with mine. Her post was in 2023, and somewhere I read that Apple and ReSound knew about the problem in 2022. And yet the problem still occurs and certified Apple techs don’t even know about it? I have worn ReSound hearing aids for almost thirty years, and have used them for phone calls, with no issue, since that feature became available. Any suggestions about what to do next will be greatly appreciated.