For anyone out there who is using Made For IOS (MFI) hearing aids, from many manufacturers but including Resound, Widex, Phonak and Oticon for example, if you are thinking of getting a phone from the new iPhone 12 family, you would be well advised to wait.
The Apple community has several threads about this and the problems are affecting many hearing aid users. The issue is that the iphone 12 randomly and continually disconnects from one or the other or both aids when it is streaming audio, for example from a website or podcast or a phone call and randomly streams static or other spurious noises to one or both aids when you are web browsing.
Unfortunately although Apple know about this, they have not yet sorted out a fix and the problems persists with IOS 14.2
I have gone back to using my iPhone XS (which works perfectly with my Resound Linx Quattros and put the iPhone 12 back in its box for the next month or two…)
Edit: Actually I am returning the IPhone 12 as it’s still inside my mobile operator’s cooling off period for on-line purchases.