Can’t stop audio being routed through dock connector in car

Asking again as there are numerous previous discussions but all have been closed without giving an answer.

I want to use google maps - with audio directions - in my rental car (recent Skoda kodiaq) and charge at the same time, but when plugging in the charge lead, the audio is redirected to “dock connector” and there is no option to select “iPhone” as the sound source - only “dock connector” is listed. I don’t want the sound to go to the car audio system (too complicated and I don’t want to listen to music at the same time).