Floor plan single-family house, 2 full floors approx. 180 sqm, 600 sqm plot

2.45m is the standard measurement, everything else will probably become too expensive. The raw construction height of 262.5cm is also located in the general contractor's construction description. But I will actually ask once because I'm interested myself. I am 1.88m tall and have a similar height in my current apartment where I feel comfortable.

2.45m is more like a 90s standard height. Typically, today's raw construction height is 2.75m minus 16-20cm of floor construction, so you should end up between 2.55 and 2.61. Less tends to feel oppressive, especially in larger rooms. But since you basically have 3 separate living-dining-kitchen areas, it might still work. I would accordingly plan the doors at 2.11m. But in my opinion, that only makes sense together. Actually, the general contractor should be able to do that for about a 2,000 surcharge.

Can you maybe sketch that out for me? I’m having a hard time imagining how you would plan the bathroom. In general, my wife has no problem at all with the open toilet; I would rather be the advocate for hiding it... ;)

Unfortunately not at the moment. I’m on vacation.

We initially had everything quite open until my wife noticed that she had no walls to put cabinets etc. against.

But the wall stubs separate the partition walls, so you can’t really place anything sensible between the windows or doors.

2.45m is more like a 90s standard height. Typically nowadays, raw construction height is 2.75m minus 16-20cm floor construction, so you should end up between 2.55 and 2.61m. Less feels rather oppressive, especially in larger rooms. But since you basically have 3 separate living-dining-kitchen areas, it might still work.
Accordingly, I would also plan the doors at 2.11m. But in my opinion, that only makes sense together.
Actually, the general contractor should be able to manage that for about a 2,000 surcharge.

Do I understand correctly that the entire house will then be higher? Or is it just the ceiling that will be "treated" differently?

The idea from ypg with the bedroom is great. In addition, I would probably place a utility room with a washing machine upstairs with cabinets for bed linen and such, and storage down to the technical room. You could also integrate the space under the stairs into the technical room. It would then be much easier to access. What I don't like is the whole window situation in the kitchen and dining-living area. We have a very similar layout of these rooms but much more windows. Both in the living-dining room and in the kitchen. There we placed the tall cabinets on the interior wall to keep the exterior wall free for access to a second terrace. I love the abundance of light in every season. And with you, that would be the west, so the ideal place for an evening terrace right in front of the kitchen!

I would only execute this square arch in drywall, maybe only after laying the floor? Then it can be removed if it no longer pleases you. However, it does zone the area nicely. We have two small walls like that between kitchen and dining as well, although necessarily because we hid pipes there and needed a support for the load-bearing upper floor wall. But I quite like it. Maybe someday I'll put a big glass door in loft style there.

Unfortunately not at the moment. I am on vacation.

However, the wall stubs separate the partition walls in such a way that you cannot really place anything reasonable between the windows or doors.

I'm not in a hurry... it will take a while anyway until the building application is approved.. . Maybe you'd like to when you're back. :)
I will reconsider the wall stubs, since it also depends on the interior design.

Do I understand correctly that this would make the entire house higher as well? Or is it just the ceiling that is "treated" differently?

Yes, the house will become higher as a result.

The 2.62 - screed structure - covering would also be too little for me, as it is for some others here. Increasing the room height does have an impact on the building application.