Your opinion on the floor plan for the ground floor

@Wastl It is a closed concrete staircase that will have a similar wooden covering on the treads as the living room (smoked oak). The riser remains white to create a nice contrast. The railing will be made of a stainless steel construction (we are not sure yet), definitely not built with masonry. An open staircase would be too noisy on the upper floor, and we have not planned a door. Next year, when the house is finished, we will know if the decision was the right one!

@aytex In the utility room, there will only be heating/electrics/washing machine/dryer + a sink in case the kids or the dog come into the house completely dirty. Our attic will also be developed (with an 80cm knee wall), where we have planned 34 sqm (floor area) as basement replacement rooms. Otherwise, we wouldn't know where to put all our stuff... P.S. I would also like an 80-inch TV.

Otherwise, I don't even find it so wrong that the staircase is right next to the entrance, I've often seen that in model houses...

Not everything has to be functional that is installed as standard in model houses.
Entering a staircase directly at the entrance is horrible. Expect that street dirt will be carried in at the front area of the door, not constantly wiped. This will be carried upstairs by socks, etc.
Slanted walls should only be a last resort if nothing else works...
The living and dining area will be difficult to furnish, it is almost square. You should also consider that guests do not come for the whole family, but only for the wife or husband or child, who then inevitably has to participate in the rest of the family life. Open and generous living spaces can be better designed, e.g. at a corner or like in North Frisia... I roughly like the design quite well
But don’t expect your house builder to design something better for you.
Therefore, think carefully whether the design fits your life, even after 5/10 years and in everyday situations.

@aytex

I would definitely do without the door to the hallway. This way you have three doors in the utility room, which creates a lot of traffic area and you have less storage space. Especially if you want to use the utility room as a storage room as well, you can better place shelves there.

What do you think of these modified versions that my wife and I have come up with?

@Bjoern
My wife thinks similarly, but I fear that I will painfully miss this short access later. This door allows a shortcut to the utility room AND the kitchen. In addition, we have a fairly large utility room. And not having a direct room into this quite large and usable room gives me a stomachache...

Another question: Do you think that a bay window in the dining area (i.e., in front of the access to the kitchen) would soften the square floor plan and allow for a better spatial separation of the seating area and dining area? Although, of course, that entails not insignificant additional costs :-(

The question of where you need this shortcut to the utility room from? You can enter directly from the kitchen. From the living room, the way through the kitchen is rarely/and only slightly longer. From outside, you usually enter the utility room through the designated entrance, especially if the driveway is on the right side of the house. So the only remaining path is from above to the utility room. How often does it happen that you are in the bedrooms and then need something from the utility room? Difficult question. I asked myself the same question once, as I have a similar floor plan on the ground floor, and came to the conclusion to do without access from the hallway.

If you change the stairs, the upper floor must definitely be included. With your first version, you will no longer get a functional floor plan in the upper floor. The living space design is simply better without the 45-degree wall.