Ground floor approx. 100 sqm, upper floor expandable (planned bathroom, 2 children's rooms, 1 storage room)

The house is not small. IF the attic is ever converted.

At least seriously consider swapping the utility room and kitchen, moving the kitchen door to the hallway (possibly moving the stairs towards the left side of the plan) so that more light can enter the kitchen and the distances become shorter.

You should also plan the kitchen yourself. In the current room, an L-shaped kitchen along the entire length would not be possible because of the utility room door. Just under 4 m for the kitchen unit would be far too little if only a single row as shown on one wall is planned. If you don’t swap the rooms, at least move the utility room door so that an L-shaped kitchen unit can run through.

Bathroom: bathtub and shower in a row; if the toilet is opposite the washbasin, the bathroom could possibly be made even slightly narrower (or the shower door opening inward so that it doesn’t hit the toilet) and the space assigned to the children's room. In any case, remove the bend from the bedroom; anyone passing through there will have a very tight squeeze.

Otherwise, please really and urgently and honestly question whether the attic conversion is financially and timewise feasible in time.
Personal opinion: After our construction site, that’s enough for me for now. My boyfriend doesn’t need to come to me saying that we’re having a child now and he will spend his free time in the attic instead of with me and eventually the child.

Nordlys from TE does not want to swap the building services and kitchen because of the smells, despite door and wall. Then an Ikea hood won't help.

If the attic is converted, the house is not exactly small. Why now forcefully try to fit so many rooms onto the floor area? Whether Schleswig Holstein or not, stretchable rubber walls are not possible with you either.

Nordlys the OP does not want to swap the building services and kitchen because of the smells, despite door and wall. Then an Ikea hood won't help.

Wasn't that in combination with a pass-through to the living room? Honestly, if you put up a wall there, access the kitchen via the hallway, and still come up with the argument about smells, you can save yourself any further words here.

No, why always get so offended right away! People talk, express their opinion, what the OP makes of it is their own business. They are the ones paying for it, they want to use it. Sometimes there is also a feeling of "I don't want to," without really knowing why not....sometimes you just have to let it sink in.

I am not sulking. But if flimsy arguments like smell are used against relocating a kitchen (and yes, even you would have supported an exchange) at some point there is simply no point in continuing the conversation. Then the floor plan is set in stone for the OP and they will no longer be receptive to any arguments.

In that case, I would rather spend my time on other things than talking to a wall.

Edit: I had to add more subjunctive here, I still think that the OP assumed an access to the kitchen via the living room, which should indeed be avoidable.

Just wait and see....