A usual standard size is also 180x90 cm ... I have that as a single, for example.
And, I don’t want it smaller, because for me it’s the same as Yvonne described. There the laptop, candles, and plant decorations are also placed. Usually, 4 people can comfortably sit quickly; for more, I have to clear away decorations etc. Currently, I’m considering replacing the table with a 140x140 table, extendable to 240x140.
And then you still have to consider that your terrace exit should also be there, which is also used to bring grill stuff etc. from the kitchen to the terrace.
And then the fireplace is still there. You should keep at least 100 to 150 cm distance from it because otherwise, it gets too hot there. Therefore, I definitely wouldn’t plan the fireplace in that corner but rather on the partition wall between living area and kitchen. Then the chimney shaft can also be shifted further to the right side of the plan and be more favorably located in one of the children’s rooms and not so much in the middle of the wall. Otherwise, you also have no option to put the table extended somewhere else.
The guest bathroom can be made a bit narrower; for that, place the shower as a walk-in type horizontally at the bottom of the plan and then place the toilet and a small sink on the right side against the wall. Shift the window a little further up on the plan. About 170 cm width is enough, which allows the vestibule to be about 215 cm wide. Then a wardrobe area can be extended on the right side, not sometimes on the right and sometimes on the left.
The kitchen layout needs to be reconsidered. The seating on the “chicken ladder” can only be usefully planned as a bench solution anyway due to the wall distance. With the existing floor plan, I would rather place the cooktop on the right side of the plan, and then put only a narrow window on the right side in the corner area so that there is space above the cooktop. The sink should rather be placed below on the long row toward the peninsula. A nice large window can then be placed on the south side there. And then the tall cabinets with, for example, the refrigerator are closer to the main work area again. Having the sink down there also has the advantage that you can do the standard work between the cooktop on the right and the sink but can also spread out toward the left and the peninsula for cookie baking, processing vegetables/fruits, etc., and the sink is always relatively close.
For a range hood, that also means less work because it can sit more or less in a niche at the right wall and does not have to struggle against cross currents.
I would probably omit the pantry, straighten the space toward the vestibule (then you don’t have to make the guest bathroom so much narrower), and create storage space under the stairs.
Upstairs, I would definitely omit these entrance niches for the office and second children’s room and continue the wall in a straight line. The bathroom is very difficult to design because of the 2 m height line. The toilet certainly cannot be placed where you put it. You can’t get off the toilet there without a headache.
I think one might have to think a bit more generally about this, also for example about the staircase guidance and where it arrives how. However, I basically like the general location of the staircase.