Opinions on our basic floor plan design wanted

Not only that.... additional costs of 17k also speak against it.

UPDATE! Here is our current plan, feedback still gladly welcome!!!

.. looks good .. as a kitchen and prep enthusiast, I would only prefer a sink/prep island and because of the spaciousness probably remove the well-planned SbS? (within the partitioned wall sections at the current sink area) .

There will be no shortage of sinks; on the window side, there will be a double sink, and on the island, another sink is planned with plenty of space between the sink and the cooktop....

And the SbS must remain

I also like it. I would probably move the door to the guest room on the ground floor further to the right according to the plan, change the opening direction into the room so that a wardrobe fits against the left wall behind it.

Why? .. Because of ice cubes, there are also great other devices. I just think it steals airiness next to the large window area. Possibly a solution would be to make the plan-right wall of the kitchen effectively longer without a connection to rows, either to integrate a SbS in this then tall cabinet wall or to switch to other refrigerator variants. Then, plan-bottom with some distance to the tall cabinet row, just a row of however it may be up to the large terrace door. Saves an annoying corner in the kitchen furniture and looks airier. Which, in my opinion, your floor plan is supposed to express.

EDIT: By the way, I agree with matte1987