Newly built single-family house with 150 sqm living area, Saarland

Ah, then it must be in the text after all. It would be more important to me than symmetry, but everyone sets different priorities :) And maybe your architect can even manage both.

Oh, and then it wouldn't work from the chimney side, it would be right in front of the window. Speaking of which. I once made a pro/con list regarding the door to the garage. I'll say this much, one of the two looks bleak.

Already significantly better (OG)... ...now bring some light into the OG corridor. But how? Glass door office is not sufficient for that! I would furnish children's room 2 like 1....

Aren't 120cm quite a common value? How much exactly is it in the picture? 130?

So in my original drawing it was about 3.5x1.8 meters. So I still see about half a meter of leeway, but then the bathroom, which is probably used most often, becomes very small.

Already significantly better (OG)...
...now to bring light into the OG hallway. But how? The glass door to the office is not sufficient for that!
I would furnish children's room 2 like room 1....

The only possibility will probably be to extend the wall to the bathroom in line with the stairs and thereby install a window at the end of the hallway.
I don't think it will harm the bathroom that much.

So in my original drawing it was about 3.5x1.8 meters. So I still see about half a meter of leeway, but then the bathroom, which is probably used most often, becomes very small.

It was about the distance between the kitchen unit and the cooking island. I think you mean the dimensions of the cooking island specifically, right? More depth there would probably almost only have disadvantages (accessibility; no standard size; ...).

Oh, sorry, I was thinking of the width of the bathroom. I actually find 1.1 meters (+-) perfectly fine between the island and the kitchen unit. But theoretically, 1.3 is also possible, I see anything larger more as a disadvantage.