You want to overtake. What is the right course of action now?

You answered correctly: In this situation, you must not overtake the truck because you cannot clearly see far enough ahead to make sure overtaking is safe. According to German traffic law, overtaking is only allowed when you have a clear view of the road ahead and there are no hazards, such as approaching traffic or curves that limit your visibility. Reducing your distance to the truck or following another vehicle blindly, even if the truck signals, is dangerous and not permitted. Always make sure the complete overtaking maneuver can be done safely without risking yourself or others. This is a core principle of defensive driving in Germany.