Plot 1250m², living area 200m², 4-person household

The main question would therefore be which house shape best takes the slight slope into account. In the previous floor plan, we always remain almost square

Show me the floor plan. Are you sure that you are allowed to drive onto your property from the "main street" or the junction of Sch*******le into the "main street"?

Until now, I was not aware that there are restrictions regarding the junction. I assume that a certain distance to the main road has to be chosen?
You will not be allowed to drive onto the property directly from the main road, because there is a bike path in front of it.

I have attached the current floor plan: However, the parents' bathroom will be altered: The door to the hallway as well as the toilet bathroom will still be removed.

In post #18 you confused me with the different drawings of the house and garage in "site plan" and "house orientation." After your remark not to take the scale literally, I did so with the site representation. There it looked as if the garage was to be accessed from the "tip" at the junction (but that wouldn't be possible anyway, since the strip with the bench and the "Welcome to Dingsda" sign separates your property from the direct street connection there). I see no problem with the ****** lane (= apparently a local access road) as now drawn here in the floor plan. At the other place, a "visibility triangle" could have been opposed (and that I consider the "main street" a country road).

Ah, I see! That means all your assumptions are correct, the main road is a lightly trafficked country road.

We are happy to accept suggestions regarding the elevation profile and accordingly house shape, if anyone is interested! :) In the current floor plan, the house shape is almost square, but we are basically open to considering other shapes – we just lack a bit of imagination there.

Yes, then build it that way for all I care, I don't see any major blunders (except that the kids' bathroom will drain near the sofa). I see the heights as so unremarkable that the integration of the house into the plot should be easy to model. I can't assess your room dimensions and wall thicknesses. I would omit the air space.

It will be possible to build like this, drainage for the children's bathroom could become interesting.

Some thoughts regardless of any consideration of the conditions of the property:
- From the garage you always walk through the rain -> entrance on the side between garage and house?
- Path to the kitchen and pantry is maximally long.
- Cloakroom very small
- long, narrow hallway on the ground floor next to the stairs with a wall below horizontally in the south
- master bedroom in the south, children unevenly oriented,
Suggestion: remove the open space, swap master and child 1 and use the north as the master section