Single-family house floor plan 160m2 - What improvement possibilities are there?

Hello,
we have a fairly square plot of 717 m2 with a terrain step. Attached is our first draft of the floor plan with a request for your suggestions for improvement.

On one hand, I think every m2 costs a lot of money and savings could certainly still be made, but I also want large open spaces. I have a big family that often visits and I myself want to have at least two children. Would there still be options on your side to reduce room sizes?

Thank you very much in advance!

Best regards

Development plan/restrictions
Size of the plot: 717m2 see attachment
Slope
Number of parking spaces: 2
Number of floors: 1
Roof type: still undecided - flat roof or gable roof
Style - modern
Orientation - the vineyard is in the west ;)

Requirements of the builders: rooms are already as desired in the plan
Style, roof type, building type - modern
Basement, floors - basement, ground floor, one floor
Number of people, age
Space requirements on the ground floor, upper floor
Office: family use
open architecture
modern construction
open kitchen, kitchen island
Number of dining seats: at least 8
tiled stove
roof terrace
garage
kitchen garden

House design
Who is the planner: first own draft for room layout

Pictures could be helpful for the property, as well as elevation marks in the drawing.

I have a large family that often visits and I myself want to have at least two children. Would there still be options on your side to reduce room sizes despite the lead time?

For desired children, I would expect the rooms to be larger. The setback on the upper floor costs space without saving money. What's the deal with the living room in the basement?

I have already attached the site plan ;) see above. Yes, I am also not so convinced about this "Lichtschacht."

Stüberl = room for tasting wine, crafting, painting, working, partying

I think an atrium in a 160m2 house somehow doesn’t fit or it also ruins the floor plan on the upper floor. I would skip that, then the children's rooms wouldn’t have such a weird shape either.

Well, is the site plan oriented to the north? It would also have been nice to have the other floor plans in a uniform orientation. A few measurements on the floor plan wouldn’t be bad either. If I remember the kitchen correctly, it had a width of about 750 cm.

The stair position needs to be checked. Overlap due to head bump hazard .. shower from the master bathroom, its drainage and the stair landing position. It also depends a bit on the floor height.

Presumably, the study is also supposed to be used as a guest room - right? I find the way to the bathroom somewhat unusual.