According to the development plan, only gable roofs are allowed.
Show the development plan or at least the passage regarding the roofs. How old is the development plan?
Roof shapes are not determined based on the Building Code, but by a design statute - often integrated into the development plan. The more restrictive it is, the more detailed the justification must be. If the positioning of the buildings, roof structures, and roof colors allow as much freedom as the aerial photo suggests, I would find the justification to allow only one roof shape interesting.
For your renovation project, you need a designer anyway. They should come up with a good justification for the deviation.