Tråd: Ryggåstak, Bandtäckning, Nockventilation

It doesn't look professional and in accordance with the rules of construction art. What the hell is a prop supporting the ridge beam for? After all, the beam is supposed to take the roof load. If it has to be supported now, what will happen after the prop is removed when the snow and wind load is added? Fittings? I don't think they should be like that. In this case, it should be hangers. Gaps between the rafters and the ridge. Generally, the rafters should lie on the beam without those undercuts that expose the rafters to splitting. I recommend inviting an inspector to check it. All of the above plus the statement that "luftspalt" is not necessary underestimates the professionalism of this company. Below you can see if it is at risk of lack (6 years old roof, also open space inside)

A single top chord is permissible when the rafters are above the wall posts. Otherwise, the top chord should be made of two layers.

Wrong type of roof.