Single-family house 143 sqm - the perfect planning?

Has anyone of you experience designing the staircase partially out of glass to make it look more open? I find little information online about experience/costs or the like.

What do you get from it? A view into the basement?

Building permits also apply to windows – in some federal states you can apparently deviate, shift, or enlarge by a few centimeters.
If you want to turn one room into two (children’s) rooms, this also leads to a redesign of the facade → windows. The builder will certainly charge for this, since a new building permit is required. But I’ve already mentioned that.
The whole thing or redesigns of the internal planning are best discussed with the builder, also because of the additional costs.

Something like that. No use, but it makes the whole thing more open and therefore nicer for me; like many things in a house.

We will talk to the architect/BU. Overall, location, price, and total size are right. Only the upper floor is not perfect concerning the children's rooms.

Attached are the fireplace and the kitchen modification, as well as upstairs the enlargement of the bathroom and two children's room ideas, all sketches.

And the children's room, on the left has 14.4 base area, 11.4 living area (upper), lower 12.8 and 10.4. We will find the best solution.

The kitchen and living area has a depth of 720 cm in the view above ... if you want to arrange the furniture like that, it will be tight, very tight.

And the fireplace position severely restricts the dining area.

And 2 children's rooms on the right-hand side of the upper floor ... it will just be cramped. Relocating one children's room to the study on the ground floor ... well, I don't know, access from the dining area?

I just see too many things that don't fit.

Take a close look at your upper floor layout: The 318 cm is not the interior dimension on the right side of the plan; that is probably max. 297 cm. Try placing beds in the rooms and at least 100 to 150 cm of wardrobe space, then try to fit in a desk as well.

But then those will be small little cubicles,

That's how it is! A child isn't really wanted with you, is it? Toddlers probably fit into 10 sqm, but teenagers? Should they then "play" outside? Or sulk in the basement?

Something like that. No use, but it makes the whole thing more open and thus nicer to me; like so many things in a house.

You can do it, but you don't have to. Actually, you don't want openness towards the basement. What you probably like about it is the (open) staircase. But the rest has to fit too, like the location of the staircase... with you at the front door and quarter-turned. You have an airy living and dining area - somewhere there has to be a quiet wall, even if it’s decorated with a large-format picture.