Training as a vehicle test engineer/certificate

Hello, I don’t know exactly if I am right in this forum, seemed to fit my question best. I am interested in an apprenticeship as a car expert and/or car test engineer. I made myself smart at KÜS and GTÜ now: but you need ALL driving license except D (is believe Omnibus?), besides the Auzsbildung there costs a heathen money. My question: Is there someone from the subject and can tell me if you can only use a car and motorcycle driver’s license somewhere such or like (if I wanted to do HU with motor bikes and cars, I don’t need a truck driver’s license). Or how else information? What else can you do with a mechanical engineering study in the direction of a motorcycle/car, except go to automobile companies? Greeting Daniel