How to change the floor plan?

The passage looks relatively narrow.
That could be a critical point.

Yes, you are right, maybe it is better to accept that 1 child - perhaps the smallest one - gets only a small room of 13.8m². The others get 2 nearly equally sized rooms. Unfortunately, the m² are not correct here. It is a program error that does not subtract the wall thickness. You always have to deduct about 13%.
Well, but it is not really perfect either. But maybe you can gather ideas and then brainstorm with the architect.

So above is, in my opinion, a critical point: the children's bathroom. It would work better if the two bathrooms were together and the staircase switched to the side with the front door. Here again a sketch of what I mean. That would mean that the ground floor would have to be adjusted accordingly. Which doesn't sound impossible to me now. However, almost all rooms would have to be redesigned. Just a thought.

You did well in the upper floor [emoji1319]
That's how I described it in #3 [emoji2]

However, I didn't find much approval for the master bathroom

Brief regards

Sometimes no other staircase works at all, and now suddenly it does?!

I rather understood that another staircase would not be unwelcome, only that no other staircase was yet believed to bring a significant gain in comfort (beyond the standard of "staircase in the parental home").

However, did not really find the parents' bathroom appealing

And even if the world collapses, I do not plan to put the washing machine and dryer in the bathroom.

Pretty long dark hallway upstairs, do we have the possibility to get light from the roof?

Flat roof calls for [Lichtkuppel]