Floor plan single-family house, approx. 200 sqm - comments welcome

I think the floor plan is moving in a sensible direction

3 small things catch my eye spontaneously.
WC ground floor: The entrance to the shower is somewhat narrow at about 60cm. It should be around 80cm.
WC upper floor: The space for the separated toilet is somewhat narrow. I would increase it to about 1m for more comfort.
Bedroom upper floor: (personal opinion) For well-being, I would position the head side of the bed against the upper or right wall.

What I would like to point out are the "details" in the bedroom. For the view from the bed, I would take a large window, similar to the ground floor below. Then you have a great view of the garden from the bed.

I like it.

In the bedroom, I would arrange the furniture differently. The feeling is not so great when the entrance door is right next to the headboard of the bed.

However, the master bathroom will not work like this.
With a rough construction dimension of 2.45, there remains about 2.40 clear. There is barely a meter of space left between the bathtub and the washbasin, rather less.
I also find the separate toilet too cramped. I would leave that out.
I would tackle the bathroom planning. If the desire for a separate toilet is so strong, one could also consider whether to create a more open concept by not strictly separating the dressing room and bathroom. There are great possibilities here.

You could build a wall-to-wall closet along the wall to the stairs in the dressing room, and on the right just a chest of drawers behind which the wall does not go up to the ceiling, with the washbasin and a standing mirror that can also be turned to the dressing room side.
That would definitely be good for both rooms so they are no longer so tube-like.
It’s a bit of a bitter pill you have to swallow with this floor plan, but it can be nicely adjusted. The master area has about 37m², which is enough space to accommodate everything nicely.
I would probably also reduce the size of the bedroom and instead enlarge the dressing room + bathroom area.

I would align the door to Child 1 with the bathroom wall. Then you could create a separate room from the square hallway in front of the children's rooms with a door to the hallway, so there are 2 doors from the common room to the children's rooms and the noise shouldn’t be transmitted so strongly through the gallery.

As for the children's bathroom, I am a bit torn whether it would be better to increase the width from 1.75 and reduce the length instead.

But these are all detailed planning issues; for an appointment with the builder, I don’t think this is bad at all.

Something's not right. What are your measurements referring to? I was just about to think about the parents' area. I used 8x4.65m as the basic dimensions. Exterior walls 36.5cm, the wall to the stairs is an 11.5cm masonry. I could imagine that for structural reasons it has to be done as a 17.5cm brick. If I draw it like this anyway, everything becomes much, much tighter. So either you used the wrong measurements for all the furniture and sanitary items, or your measurements are incorrect. That doesn't make things easier...

I took the basic dimensions as 8x4.65m. Exterior walls 36.5cm, the wall to the stairs as 11.5cm masonry. I could imagine that for structural reasons it has to be executed as 17.5cm brick.

Yes, on the left side I also see that it will have to be load-bearing. But:

You will only bother us again with the “professional” drawings

That will be best. Everything (essential) that should be discussed before a conversation with an architect I see already said.