Single-family house (2 floors + residential basement + developed attic) approximately 200 sqm - changes

Yes, the gable can point wherever it wants. But we also have the 50 degrees for installing photovoltaics. In that case, the roof only makes sense facing south. That is also the street that leads us into the residential area. A gable perpendicular to that would be very visually confusing. After all, on the opposite side, the gable is also oriented that way, and according to the plan, on the right there is a flat-roof building set far back. The area in front of the rear house is supposed to be de-sealed sooner or later regardless of the new building! 9 by 9 meters with 2 floors and the roof on top is only about 5.40 plus the roof. That is not a tower, is it? At least if the basement is completely underground.

9 by 9 meters with 2 floors and the roof on top is only about 5.40 plus the roof. That’s not a tower, is it? At least if the basement is completely underground.

Of course it is. You run up and down 4 stairs your whole life. Do you want that?

This is very basic again... But I have never lived lower than the 2nd floor in my life. The basement is certainly not regularly used and there are 2 children in the attic. I find basements underground without residential use, ground floor and attic with main use, attic for the kids not concerning. Above all, the stairs must currently show that they really have enough width and length.

But we also have the 50 degrees to install photovoltaic systems. The roof only makes sense facing south.

Why 50 degrees? I'll attach a table from the internet since I can't post links. Source: Photovoltaic-Web
An east-west roof is not worse for photovoltaics because it produces power distributed over the day and especially in the morning and evening when most people are at home and use electricity.

It's not about profit from feed-in tariffs but about offsetting as much consumption as possible in winter (when heating is used). For that, a southern orientation at 60 degrees would be optimal. Of course, this results in significantly less in summer but more or less a somewhat linear output throughout the year at a lower level. In short: a bit more in winter instead of almost nothing and significantly less in summer instead of a lot (which is still enough).

I will only manage all floors this evening. Unfortunately, my program will not allow a proper display for the stairs.

A quick 5-minute sketch with pencil and readable numbers is honestly more appropriate than colorful illustrations.