Single-family house - approx. 150 sqm - without basement - Who has ideas? Thanks

Regarding the upper floor window
I'm a bit lost here, do you mean a second window on the east side of the upper floor bathroom? Under the upper floor bathroom is the utility room, in the living room on the east side I wanted to avoid a window, because otherwise you look at an ugly wall from the neighbor (about 3.7m high).

Regarding the PC corner:
At first, a video editing station is planned there (could later be an open pantry), later I could move everything upstairs or to the attic, but do you still think that there will be very little daylight there, in front of me would be the large terrace window, right?

Regarding the ground floor: I would have the door to the terrace from the kitchen open the other way around. After all, you want to go out from the kitchen and not from the pantry, right?

I would also check all the passages and measurements in the kitchen. The passage above the island, along with the "wall stub" on top, looks very tight to me.
I actually find the original bathroom layout on the upper floor better. One thing to keep in mind is that glass walls need to be cleaned more often than tiled walls, depending on the lime content of the local water and personal preference for cleanliness.

I meant a window in the living room. Ugly walls from the neighbor only bother for the first 2 years. After that, wisteria or whatever is planted there and it looks beautiful.

In front of the terrace window there is a wall or tall cabinets planned, right?

Speis means pantry, so the separate part you planned above the kitchen.
So definitely have the door open the other way, otherwise you'll always have to slalom around the door.

It's best to already go into more detailed kitchen planning NOW. Definitely don't start too late.
There are helpful forums for that, for example.
Once the windows, connections, and walls are built, it's too late.