Newly built single-family house with 2 full floors and a double garage, 150 sqm

ops: Interesting. I don't think we've had that before. So you don't install cabinets, is that what I gather?

Exactly. We want to install the shelving system.

The heating circuit distributor on the upper floor is located exactly where I would prefer to leave the option to move the door to the dressing room - therefore, I would have it moved to the opposite wall.

The heating circuit distributor on the upper floor is located exactly where I would prefer to leave the option open to move the door to the dressing room - therefore, I would have it moved to the opposite side.

We deliberately decided against the door to the dressing room. The reason is experiences from people we know. They had the dressing room as a walk-through room and always had problems with dust (we are not planning cupboards but an open shelving system). We want to at least reduce that problem this way.
But it is definitely an interesting point.

We deliberately decided against the door to the dressing room.

I suspected that already, but it’s no reason to completely block yourself from changing your mind.

(we are not planning closets but an open shelving system)

Good for casual clothes, mediocre for everyday clothes, no stroke of genius for evening wear.

With a width of just under 2m for the dressing room, I see cabinets (with doors) as difficult to realize anyway. And then the double door, which costs valuable space.

And then the double-wing door, which costs valuable space.

The wing door was a special request from the wife. Here it was clearly a case of "Function follows Form."

I already thought that, but it is no reason to completely block oneself from changing one's mind.

You are of course right about that. I will ask around; maybe something can still be done.