Floor plan planning shortly before submitting the building application

That's funny. Although rather sad.

You could at most reduce in the [EG].
The [OG] is already "relatively" low at about 2.60m.

But how much do you have to reduce??
It can at most be 15-20cm – as if that would affect the "external appearance" of the building.... unbelievable the authorities

I am curious how much they want to lower it there. In the upper floor, almost nothing is possible. Bringing the ground floor to the same height also "only" adds 23 cm.

What I do not read out is that a change from a hip roof to a flat roof would bring something, since the wall height is explicitly mentioned here.

What I don't see is that changing from a hip roof to a flat roof would make a difference, since the wall height is explicitly mentioned here.

Yes, the roof height is completely irrelevant here; it’s only about the wall below the roof. How high was the room height in the previous building, or the eave height of it?

I don't know. There used to be a single-story bungalow with a blunt-angled gable roof there.

In the upper floor, practically nothing works.

Why?

I don't know. There used to be a single-story bungalow there with a blunt-angled gable roof.

And you haven't measured it, and don't have any drawings of it? - you should ask the neighbors (and have them show you drawings), besides the absolute dimensions, the tolerance range is also interesting. For both, that means raw construction height and clear height.