iPhone Apple Maps Navigation Audio not working with car

Background:

iPhone SE latest model with

latest iOS version 17.6.1

Voice navigation works

properly in stand-alone mode, Bluetooth on or off.

iPhone with Bluetooth turned-on

connects properly with car for voice calling & receiving. Car is a GM.

Google Maps app on iPhone

voice navigation is working properly with car.

Apple Maps voice navigation

worked with car until several months ago.

Now:

When iPhone with Bluetooth is turned on & connected to car bluetooth Apple Maps app voice navigation does

not work with the car or itself – neither has voice navigation! Map app on-screen nav works properly but no audio.

When car radio/Bluetooth is turned off, iPhone app voice nav resumes as normal.

Family member with iPhone 12 Pro Max has same issue on their Honda.

I read the many prior posts on this site an double checked every suggestion posted with no change.

All new suggestions welcome but action by Apple tech is clearly needed

Thanks.