We have been working on it forever (years ) and for US it fits so far.
I don't see it that way. There are many planning flaws as well as sloppy and thoughtless execution (by architects).
That's true, the building permit basically only confirms the exterior view, how it fits inside does not matter in this case
I would withdraw the building application.
Especially with windows, there are quite a few tricks you can use. But that would go beyond the scope here – quite literally.
Of course there are tricks. But two windows in line that are only approximately as wide, i.e. supposed to appear as wide as the others but are not, is counterproductive. You then consciously choose different ones so that it looks intentional (and not incompetent).
We wanted the 2 WCs, we are then about 4 people + friends/boyfriend/girlfriend. In the morning it can take longer to distribute ourselves well
That is exaggerated thinking. Everyone has a different rhythm, two will fit. The space is needed in all areas. I will come back to that.
And when we are old and only live on the ground floor, the bedroom bed just has to be moved into the office,
Then I'll start there: The office has no space for a double bed and/or a wardrobe. If you cram in and do not furnish properly, there is no sufficient walking space. The staircase seems too narrow and with 14 steps also too short. I read somewhere about 2.40 height, which is too low for a long narrow room like a corridor or open space. (For explanation: Others find my old-fashioned 2.50 already borderline, so I am not spoiled.) The window band on the facade is far too long. Does not match the rest of the windows. The band also seems to run past the staircase below... The bathroom on the ground floor looks like a laundry room on a farm. This setup does not make sense to me, nor does the washbasin under the window. This place is not barrier-free either. The architect clumsily drew a wall that lies in front of the double door to the open space. By the way, this offset also exists on the upper floor and I don’t understand it. Since I pay attention to having at least nice sight lines, when everything already has to be smaller, different, cheaper, I am of course extremely disappointed about this corner. I mean, a view through the double door to the stairs with nice decoration from the dining table could be beautiful, but here it is not. Kitchen counter with stove without lateral storage space has nothing to do with kitchen planning. I hope that will be planned separately. Open space: There are no dimensions, but the furniture seems shown reduced in size. One terrace door is too few for a large beautiful garden. Upstairs there is no partition wall for a bed (headboard often higher than a windowsill). Change proposals without withdrawing the application: Enlarge the stairs to normal size, shorten the window band below to a normal windowsill height. Replace both bathroom windows in the north with a single narrow casement window. Connect the double door to the open space opposite the stairs with the stairs. Swap office/bathroom, also mirror the open space. Mirror the house almost completely, keep the corridor as is. Why? Bathroom near entrance, stairs near entrance, kitchen near entrance, basement access near entrance. Office (later desired bedroom) away from entrance (more privacy). Use toilet room as storage room, cloakroom, or add it to the office. Remove window toward the dark hallway on the ground floor. Deliberate placement of kitchen furniture. Double door instead of a window. Upstairs is of course mirrored accordingly. Furnish the bedroom and plan windows accordingly. But the best would be to raise the room height to at least 2.50 m. Rooms should not be higher either, since the open space actually becomes a corridor.