The concern with a UP receiver would be hearing processor noise, but the sonova microphones are pretty quiet. If money is no object it’s worth a try, but it might also be valuable to have them send pictures of the build before they make it–the UP is often too big to fit well into the ear canal and so has to sit in the concha a bit awkwardly.
Ugh. She can have a different opinion, but she needs to talk it through it with you. That’s patient-centred care. I’m sorry that happened.