180 sqm non-replacement house, best adaptation to the plot?

why do I have to think of 's design when I see the pictures, outer shape, open inside and incredibly variable in terms of room layout

That's all.

That means you have 17 m of building window depth (20 m, but the building limit coincides with the southwest property boundary, so you have to subtract 3 m building setback there if you disregard border-privileged buildings) (?)

You have 17 m building window depth (20 m, but building boundary congruent with the southwestern property boundary, so 3 m building setback must be deducted there if one disregards border-privileged buildings) (?)

No, unfortunately not:
the rear building boundary is about 2m behind my rear property boundary, so the building window is calculated as follows:
Property depth = 25.0m N, 26.2m S. From these 25m, 7.5m are deducted for the front, street-side building line, and 3m (or 0.4 x wall height, so possibly 4m due to gable wall) rear building setback, resulting in a maximum exploited building window depth of 14.5m,

To the northern neighbor I count 3+1m distance, since there may be a parking space/garage there, to the southern 3m.

foreword:
the discussion is already achieving exactly what I had hoped for: it forces me to examine much more critically whether a concept really corresponds to what I/we want, whether it really fits the property.
At the same time, I certainly have to provide more concrete details so that the discussion is not prematurely fixed on the “northern barn.”

You have the garden facing west through the garden in the south.

Without having read the text: long and narrow on the north side, light through southern sun in the house, living room in the west

Yes, those were also my thoughts, and if you do it that way, it will certainly be at least pretty good (7.5x13 would not be sufficient on the ground floor though).
Now the “but” becomes sharper: if you do it that way, then: you open the house on 13 meters length towards the southeast, and exactly to the southeastern neighbor on the full “broadside.” At the same time, however, this is from the street view a classic SOUTHWEST and not a SOUTHEAST property, moreover one with an unobstructable southwest location to the park.
Should one therefore also consider a solution that is more park-oriented and southwest- rather than southeast-oriented?

If you are interested in my two cents

But absolutely!

why do I have to think of @pagoni2020’s design when I see the pictures, outer form, inside open and incredibly variable in the room layout

Yes, accurate, and thanks for the hint, but also the opposite property situation: here a southwest property, there a northeast property.

so regarding the possible 125 sqm.
You have a child. That will surely gladly give something up now and then.

So, child has given up, :D: attached are the first drawings for alternative 4/angled for the dining room.

There is also a narrower version of this, visually slimmer in the living room area and with only one room to the west above.

The rest follows tomorrow.

On the computer, it definitely looks nicer... :confused:

It definitely looks nicer on the computer...

Better to have a recognizable drawing in hand than the Picasso on the roof ;-)

I think the living room lacks a bit of "retreat space." It almost only has windows. Piano and fireplace together will be difficult for the piano. And it has kind of gotten the "kids' table spot," there in the passageway.

And I don't like an L-sofa either. But that's just my taste. ;)

Otherwise, I think it's a nice floor plan. I would buy a house like that.