An elaboration on how complicated call handling can be with hearing aids (and how I wanted AirPods-like behavior): I assisted someone with purchasing hearing aids a year ago, and we first had a pair of Philips and returned them within a few months because they only worked with iPhone for supporting phone calls with the microphone on the hearing aids themselves, for Android it didnt work. Even the next generation Philips 9050 that supported Auracast didnt support this.

We ended up with Phonaks rebranded as Sennheisers. The audio quality during calls may not be as clear as a separate mic (what i believe you refer to as oticon), but from a user experience its nice to not have to fish out your phone to answer a call or wonder why you can hear the other person but they cant hear you.

Note that my complaint here is specific to Android support.

Seems a bit sad/ironic that it sounds like the solution in OP's case would be to switch to Android for that exact behavior that your side didn't want. (And that switching to iPhone would bring that "feature" in)

I personally use iPhone and I do prefer to leave phone in pocket for my phone call. But it does seems like a massive oversight to not make this configurable.