Floor plan design for a single-family house for a young family

Do you really want your son/daughter in their teenage years to come home with a girlfriend/boyfriend and maybe find you chilling lightly dressed on the sofa at a late hour??? That is my biggest concern...

Regarding the bathroom: Put the toilet where the shower is. Place the shower where the sink currently is, with a built wall next to the toilet and two glass doors, or with a built tub parallel to the carpenter and two glass elements in front and back. An open shower will probably be too short? 1.50m probably as a guideline... Then have the tub installed somewhat diagonally in the corner, but it can also stay as it is. And put the sink on the right wall so that light falls on the mirror from the left when you stand in front of it. I think the window should be able to stay as it is.

I find a 19 / 25 step borderline. Access to room three is not so great with the large wardrobe.... especially since I would be interested to know if the doors even fit there.

The doors do indeed look narrow. Maybe at that spot it would be better to consider slanted access to the rooms and thus straighten the wall between the rooms. A cupboard can also go on the other side. For the stairs, one more step might still fit, just barely or...

There is really a lot going on here, very nice So, one by one:
: We approached the matter quite naively and over time we had to realize that some of our wishes contradicted each other (e.g. compact cozy house <-> ground floor and upper floor separately habitable). Also, through the talks with the architect, we only really became aware of our own priorities. We are very happy with the principle of the current design, even though it still needs some fine-tuning
: I think you can see the staircase one way or another. I’m curious too and might like to see who is coming and going with the kids...
And I have to model the bathroom layout, thanks for the input. Light from behind at the washbasin probably wouldn’t be disturbing, or why is that bad? The sun doesn’t come in from the side anyway
: The stairs are quite steep, that’s true. It would be possible to add one more step, but then it would be longer and move closer to the edge of the gallery, I have to calculate how much space would remain in height then.
: Our architect said the doors would work, so I believe him. We requested the corner for the second bedroom closet because without a basement and attic we need storage space and otherwise the bedroom would be a bit too narrow to fit a closet there.
: The staircase going down to the living room and up to the bathroom lets the two floors merge more into a whole and is more coherent than if the staircase led directly from the front door to the bedroom (my opinion).
: The floor plan is really very close to ours, how far along are you with the house building? The staircase as storage is also planned with us, depending on how spacious the drawn-in wardrobe will turn out to be later.

So most would probably turn the staircase, but due to the room layout upstairs, we like it better as it is

So, I think light from the side is better. Even if it is north, light still comes into the room during the day. Otherwise, you block the natural light source with your own body. As I described the bathroom, friends of ours have it. It feels very spacious and nice... They have the built-up shower wall parallel to the room wall and glass swing doors at the front and back. This makes the room feel very open and spacious, in my opinion.

Oh, and reconsider the furnishing in the living room... That way you'll regularly have to close the blinds in the west in the afternoon because they glare on the TV...