How Phonak Marvel and onwards work is very differently to the older Phonak Venture which I also used.
Phonak also use Classic Bluetooth so all theses features of MFi also won’t be there.
Have you tried the settings I explained in my first posts?
Regarding phone calls, I pick up no background noise but I was explained about where lows over power the highs from the hospital. @PeterH knows what this issue is actually called. I have no issue with background noise at all but then I’ve had an audiologist who saw me 30 years ago when I was a baby so is experienced.