You need to drive an old car! And new cars should not have all this shit. That is the main Solition. Same on Phones, first you need a trusted device, than you can add a shield. You can drive an old Car but i know no Smartphone i fully suggest. I would suggest to use a mobile pc instead, but this is not comfortable, because of this i use a Google Pixel with Graphene OS and use flightmode but WLAN on.