Need optimization? Single-family house with 130 m² + basement

Of course you can do that, I don’t find it ugly either. In practice, however, it is prone to errors. Water comes from both sides and can’t go away at first; if things go badly, it pushes the water into the wooden structure. In a rainy autumn and mild winter, this can cause the roof to rot away. Better to direct it to the side or forward, so the water can drain away.

The staircase does not have to be straight, it could be 2.30 meters wide instead of 2 meters. At least that's what Katja meant. However, with the house size, you have to accept some compromises.

Have you furnished your floor plan yourself by hand to scale?
The dining area is very tight. I would get rid of the counter at the kitchen. There is no wardrobe either. Space could be somewhat regained by removing the shower on the ground floor. Only 5 people with 1 shower is also not optimal.

I like the upper floor from better. I would adopt it as it is.
Also the roof. Yes, you have drainage. You also have a potential leak. When will you notice, for example, that the gutter is clogged?
The snow from both roofs gets stuck in the groove and also stays there longer. It's okay when new, but what will it look like in 20 years?

I would arrange the house differently on the plot.

here is another illustration.

We don’t need to argue about taste in the illustration – that’s exactly what I’m saying: it comes across differently in real scale. Almost all houses look great in illustrations, but as you can see from your own example: in illustrations, the word "detached single-family house" is also very literal: as far as the eye can see, no neighboring buildings. But on the real plot of land, you never see your house from twenty meters away (still standing on your own lawn!), and your eyes are nowhere near eave height.

The staircase doesn't have to be straight; it could be 2.30 meters wide instead of 2 meters. At least that's what Katja meant. However, with the size of the house, you have to accept some compromises.

Have you ever furnished your floor plan by hand to scale? The dining area is very tight. I would get rid of the counter near the kitchen. There's also no wardrobe. Some space could be regained by removing the shower on the ground floor. Only 5 people with 1 shower is not optimal either.

I like the upper floor from better. I would adopt it as is. Also the roof. Yes, you have drainage. You also have a potential leak. When will you notice, for example, that the gutter is clogged? The snow from both roofs stays stuck in the groove and also lies there longer. New is okay, but what will it look like in 20 years?

I would arrange the house differently on the property

Thanks for the feedback. Yes, the furnishing will be different. The kitchen will be narrower and the counter and the "stools" or as called here: "armchairs" in front of the counter will also be smaller. Our current couch will fit and so will the table. With the size of the house, you just have to make compromises... but we will prepare by installing a lintel between the living room and the office... meaning that it could eventually be opened up. We will place the wardrobe in front of the shower. At least for jackets and a few pairs of shoes... if I had to store all my shoes & bags, I would need a separate room ... but we don't want to do without the shower.

However, I will reconsider the shed dormer and discuss it again with the construction company!

With 5 people, quite a bit will add up in terms of jackets and shoes.
But just as I said, I wouldn’t do without a second shower for 5 people either.

Really draw in your furniture and then you’ll see if it fits. Think about the traffic areas and distances.

I will, however, reconsider the dormer and discuss it with the construction company!

If you really want it fashionable: a side slope of this roof part would also be quite "in" and would not have the described storage problem.