Using Bluetooth ear connection but the phone’s microphone

I have a severe hearing loss and use hearing aids. My hearing aids Bluetooth to the phone, which is great to hear. There is no microphone in the hearing aid connection and I use the phone’s mic.

This works well for standard calls, BUT not on Messenger calls. (Weird!!!) The phone’s mic won’t work.

it appears that in messenger, the phone Bluetooth is looking for a Bluetooth mic.

ls there a setting in Messenger to use the Bluetooth ear connection and the phone’s mic?

Thanks in advance