Floor plan: A life in the dream or nightmare house?

The problem is that there is a 3-story apartment building in the east (see plan gray marking). Due to the extension in the north, the house also moves a bit closer to the sun towards the south.

We would like to have an office + laundry on the ground floor, which is why there is an imbalance between the upper floor and the ground floor. So far, the extension has not really been well received – but what alternatives would you see?

Privacy can also be created through outdoor landscaping. Alternatively, it would also be possible not to darken the entire terrace, meaning only part of it is covered or only a privacy screen is set up on the east side.

Overall, the extension simply seems nonsensical. Improvement: position the building mass much more compactly; it doesn’t have to be a cube right away, but at least clearly reduce the outer shell: this saves space on the plot (more green), is more energy-efficient, and lowers construction costs. The balcony may be stylish, but based on experience it is rarely used (possibly when the children are older for secret smoking ;-) )

If your strong wish is to have the laundry on the ground floor, nothing can be done about that, but I also find it pointless with a planned basement: I think not only about the space but also about the noise. To make it convenient, alternatively a laundry chute could be planned to better get the dirt to the disposer. I see it similarly with the "Speis": it is primarily a storage room that you don’t need to access every 5 minutes. So I would either simply enlarge the kitchen with the pantry or, as others have already suggested, move it to the basement.

If the basement is omitted for cost reasons, of course that’s not possible; then, personally, I find there is a lack of storage space.

Problem is a 3-story apartment building in the east (see plan gray marking).

I have understood that and also repeated it. The question I ask myself is whether you give a neighborhood too much weight, so that you consistently plan your house like a townhouse. I don’t know you and cannot estimate whether you generally exaggerate things a bit more than they actually are.

but what alternatives would you see?

After the failed aesthetics and the dreamy wasting of living space including basement, which do not fit the budget at all (your flat roof construction already costs half a million), I recommend an architect. With your budget, you build a plain compact house without a basement, but with an attic.

Estimate >750k€

plus outdoor facilities, I would also see it that way, all-in depending on the level of equipment you can already be close to a million.