Floor plan proposals - What works, what doesn't?

Yes, that is the plan. Appointments at two kitchen studios have been made.

Between the wall and the window there should be 65+ of space if possible, so that cabinets can be placed behind. I would move the terrace door further towards the cabinets in this respect. That also looks elegant -> walking space of one meter past the tall cabinets to the terrace. Possibly kitchen work surface on top as a U?
For the double door to the open room, I would personally limit the side of the tall cabinets with a real wall. There a calendar or pinboard can be hung if necessary or a light switch can be installed.

In short, greetings

I would omit the floor-to-ceiling windows in the children's room bay window and only install windows. Then the desk can be placed directly by the window, which provides more freedom of movement in the room.

I would only make them two-part, i.e. open only at the top, but would not do without the translucent parapet (possibly frosted glass).

This draft will become the execution plan. [...] So the kitchen must be finalized now, not sometime later.

And the same applies here: take the scissors yourself once in a while, don't just have others draw. Measure the existing kitchen. Place a notepad next to the toaster / coffee machine. Write down what would be more practical if changed.

Also in the bay below: windows open only at the top. Patio door where the window in the corner of the kitchen currently is. A full dining area in the bay and away with the muesli bar at the kitchen island. Kitchen as a U-shape, possibly stepped, with the tall cabinets on the wall to the guest room.

More and "my" bathroom gladly if you participate more

I always work with... Still, I think you can't compare the kitchenette of a rental apartment with the kitchen of a house... I only have one line now... it is definitely too little... Otherwise, I already have certain ideas about how it should look... however, I like to get advice or inspiration at the kitchen studio... and I don't find that bad either... what bothers me right now is only that it is too small... Otherwise it's good... after all, it is a new apartment from 2012... that means it is very modern and well equipped and I also know that you are not a fan of those drawn-in fake furniture... you have already mentioned that

I always work with...

... well, the craft scissors still haven't been found. But with those, you can cut through the knot.

Still, I think you can't compare the mini kitchen of a rental apartment with the kitchen of a house...

As-is vs. to-be comparisons are somewhat more complex when triangulated, yes, but just as useful.

not a fan of those drawn-in fake furniture... you already mentioned that

Better I annoy you with it now than you understand it when it’s too late. It’s too late when the real space is there, into which only the fakes fit. Then you go to the kitchen studio and order a kitchen with the wrong dimensions, because you built the matching house to it.

If you move the patio door by about 20/30/40, you have an imaginary dividing line for your kitchen. This should be used as a reference... judging by the measurements, I estimate that a nearly square island would fit best. Many here are against placing the stove on the island because of cooking odors and swear by stove placements along the wall. It would fit quite well here next to the patio door, as I see the island dimensions at 1.20 x 1.20/1.30. A stove would look odd there and the space on the left and right would be wasted. But this is just a suggestion

Best regards, Yvonne