Portofino & Google Maps (Non Apple CarPlay Car)

I sometimes use Google Maps on my iPhone to guide me to locations.

The iPhone is connected to the car using Bluetooth. When I use Google Maps I've found that voice instructions are not playing though the Porotfino's speakers. However, if I'm on a phone call voice instructions are played through the speakers.

I checked the settings in Google Maps and in the Navigation Settings I have 'Play voice over Bluetooth' set to on. Voice instructions do not work.

So I set 'Play as Bluetooth phone call' to On. The Google Map voice instructions work, but every time an instruction is given a window appears in the Infotainment screen showing a phone call in progress, which is a little annoying.

I can stream music stored on the iPhone and Spotify without any problem.

Has anyone else had such problems?

Does anyone know if there is a way to just have the voice commands without the annoying pop-up phone screen?