Problem with 15 ProMax staying connected to my hearing aids during phone calls only

I, too, had problems keeping the 15 ProMax connnected by Bluetooth to my hearing aids. I never had problems with my IPhone XS that I had for at least 4 years. I had no problems for the first couple of weeks after buying the phone in early Sept. Then I went to Poland, Hungary and then Norway until Sept 24. I'm not sure when the problem actually started though. It definitely been a problem for the last week. I have spent HOURS on the phone with Apple Support, and on the 3rd call, we finally found a solution! The network settings had to be reset. So far so good. Will update if this didn't, in fact, work permanently.