Single-family house, staggered storey, prefabricated construction method

The kitchen does not work like this, the spacing between the rows is too large. What is this box to the right of the island? Do you really need 3 showers? Child 1 should still get a window on the left side of the plan. Is the entire upper floor really supposed to become a terrace? For what purpose? I would rather opt for a green roof. You can still walk on it or put up a drying rack. I like the layout of the parents' area (access through the dressing room, bedroom not a walk-through room). Is the closet space in the dressing room sufficient? It might be nice to have a window at the top of the bedroom, from which you can enjoy the view of the fields from the bed together with the rising sun.

The vertical wall to the right after the front door we wanted to shorten upstairs to get the kitchen island further down. We looked at the distances between the kitchen rows once in the furniture store and wanted to aim for 130 cm there. To the right of the island is the SBS refrigerator. As stated above, exactly the 2 changes of the windows in the bedroom (horizontal skylight window) and Child 1 (view there goes over the garage to the cemetery) are planned as you suggested. On the balcony there should be a small jacuzzi and loungers, possibly also a seating area because of the view.

Moving the living room bay window downward would slightly reduce the terrace, and maybe we would still need a support at the top right of the plan, right?

The terrace above will move along.

The terrace above moves along.

The slightly shrinking terrace is below for me, the balcony above. But yes, the balcony above does not change, possibly an additional support would have to be installed at the top right of the plan, basically under the bedroom.

We wanted to shorten the vertical wall to the right of the front door at the top to be able to bring the kitchen island further down. We had looked at the distances between the kitchen rows in the furniture store and wanted to get to 130 cm there. On the right side of the island is the SBS refrigerator.
As written above, exactly the 2 changes of the windows in the bedroom (horizontal skylight window) and child 1 (view there goes over the garage to the cemetery) are planned as you suggested. A small jacuzzi and loungers are planned for the balcony, possibly also a seating area because of the view.

We have a distance of 100-110 cm from the row to the island. I find that comfortable. Two comfortable bathrooms I basically find good, although I wouldn’t need 3x shower/WC. 2x bathroom + 1 guest WC in the entrance area. But then I would have one full bathroom or shower per floor.
The children’s bathroom is probably done more often nowadays, although from personal experience it can eventually be that you rather don’t want your teenagers directly next to your bedroom + bathroom, but maybe on the ground floor with their own shower and the parents’ area upstairs.
For a similar reason, the master bedroom could be bigger or swapped with a child’s room.
So.... up there your big, great bathroom, on the ground floor a shower-WC for guests/growing children and a small guest WC at the entrance for normal visitors.
That’s how we have it here and that’s how we will do it again when building the house now.
Somehow I don’t yet have the feeling of spaciousness on the ground floor, and the living room also feels enclosed. But you will surely get suggestions here. I also like generous glass surfaces, here for example much more generously behind the dining table, at the seating window. Maybe a really big sliding door could go there as well.

The kitchen layout is awkward ... the island is actually quite short for cooking/washing. A side-by-side fridge freezer in an inconvenient spot, and with the fridge section on the right, it’s also not very easy to use from the main work area. The prominent side of the side-by-side facing the living room is visible. Actually cooling-washing-cooking.

Overall, stairs/dining/cooking with over 50 sqm is actually quite generous, but somehow not well divided.

The pantry is actually unfavorably located and also awkward to access.

The sofa position is also somewhat unusual ... is there a good view to the top of the plan = east?

Due to the relatively deep covered terrace in front of the kitchen, there is also rather little sunlight in this area.

But if I move them to the top of the plan, the distances from the garage, front door, and also the kitchen (which would then be at the bottom of the plan) are too far for me.

Yes, then even more should be changed. For me, this draft here is close if you plan standard in symmetry. Then rotate the staircase, add a bay window extension, and it's a plan.
Nevertheless, Ben should simply mirror the axes once, so Samis’ west is also appreciated inside. And as already said: you can still tweak quite a bit on the corridor extension etc. For me, all that is too little for "afternoon onwards."

What do you find not good about the upper floor?

Walk-in closet of almost 9 sqm for few cabinets, quite little bathroom for 16 sqm, kids’ bathroom with 175 width is rather borderline with additional extra length (a parallel thread reveals that 2 meters is already quite cramped).
Kids’ bathroom wastewater is where, in the dining area?
Exterior appearance???