Build a double carport

It was in reference to the statement that I need a building application... I am already aware and clear about the structural stability, after all, no one wants to build something with toothpicks here... 12x12 cm and 6x12 cm is what the planner specifies who, as I have just learned, can also provide a structural calculation. The question was more meant as "That seems meager, would you also do it that way or rather play it safe and build more solidly if you're going to build anyway?"

I would install exactly what the structural engineer has calculated (with the appropriate dead load and load-bearing capacity according to the necessary requirements for snow, walkability, etc.).

What good is it to you if the roof beams are 20x20cm, but the supports underneath collapse?