Floor plan of a single-family house on a hillside with a basement

Sit down, six!! Please don't tell me this was designed by an architect?!!

He is an architect and has many years of experience. Unfortunately, he is a somewhat older semester. You don't all need to tell me that it's bad... I see that too... Do you have any ideas on how it could be done better?

Number of people, age: 33,33,6 (another 2 are supposed to follow)

Where does the third child sleep? Would start at zero, somewhere else.

PS: Wow

Everything new
Is a child's room missing

Try turning the staircase 90 degrees
KG
Guest and storage room become 1 room
Workroom slightly larger, laundry smaller, then this corner disappears
House connection room becomes wider if the staircase is turned.
I'm not sure if it works like that at all. It's quite narrow

EG
Everything new
Building services get removed. Then turn the staircase

OG
I would remove the walk-in closets
Remove the bay window - it doesn't fit visually at all
Remove the mini storage room
Maybe swap the bathroom with the child's room. It should also be easier in terms of drainage

Do you have any ideas on how to do it better?

Yes, change architects. Honestly - this makes no sense. You want to build 3 floors - that will surely cost half a million. Do you seriously want to save on the architect there? At least the design has to be perfect. Afterwards, someone else can handle the execution.

Poor designs are usually not due to the architect's birth year, but rather to either a lack of communication or the client's wishes that cannot be implemented because the plot does not allow it.
Are you sure that the landing staircase was not mentioned by you?
I also wonder what the slope is like or is supposed to be, when you say that the desire is for floor-to-ceiling windows in the basement. In the elevations, the windows are partially shown, and the ground is uneven. Besides, you need to stay with two stories.
Then the statement about the kitchen. Does it already exist?
And where does the idea for the bay window come from?
An architect doesn't just come up with that on a whim, right???
Just moving the garage like that, I don't see it either, after all, 5 meters from the boundary must be maintained?
Basically: rotate the staircase, execute it without a landing, then there will also be more space in the northeast for the bathroom and so on.
Strike the pantry, it can then be placed in the unwanted technical room on the ground floor.
Replan the upper floor, placing the children's rooms (2 or 3?) in the south.
Bathrooms should be above each other and not have the drain installed in the dining room in front of the panoramic window... hehe.