City villa single-family house floor plan after 6 months of planning phase...

Where is the street then? Also in the south?
Tell me, why an East garden. Or think about it yourself.
It’s probably a bit too much house for the budget....
Attention!
I would expect to also want to sit in the entrance area in the evening. I would probably swap the kitchen and living room so that the kitchen is closer to the main dining terrace.
But watch out: the design might have to be downsized... then many things won’t work anymore. Big works in every way. You have 200 sqm now... that probably has to be reduced to 130/140.
What should be included in 280000 or what is not included? For a shell house with packages, that might work...
The guest WC also seems to be just a gap filler for a too large house... I would never put it in the middle of a house... if there is a blockage, maybe everything has to be dug up.
I would say: little planned on huge size!

What should be in the budget?

Garage too narrow. The slim driver can just about open the door. Buckling the kids in is not possible. Better a carport.

Draw all the furniture to scale including movement space.

The entrance/hall/WC area needs to be revised. Feels cramped because of the squeezed-in WC.

The upper floor is okay. Possibly swap the rooms and give the bedroom the north/west room.

I would consider a small additional room. A storage/ironing/gaming/I want my peace room often called an office is missing.
You watch football and your wife talks on the phone, one must go to the bedroom otherwise you disturb each other.

So, then I'll start.

As for the budget, that referred exclusively to the house without connection costs, without earthworks and other incidental expenses; that is the turnkey price presented almost identically to us by 2 companies, as KFW 55 with Ks panel elements.

Garage absolutely correct, however, in our case it will rather be used to generate storage space.
We currently also have a garage that is bigger than the one planned but we don’t use it for our car, rather for children’s toys/devices, wintering the pool, etc.

Entrance area is the question, is bigger better there? We somehow think that it might be wasted living space??

An additional room would be great, but how and where? I see no potential for that on the upper floor. And I really can't think of anything on the ground floor either; personally, I would prefer the guest WC to be a bit bigger there since it will certainly be used often by our kids or it would be cool to later install a shower there to use the ground floor as a separate apartment in old age...
We wanted the ironing etc. in the utility/technical room anyway, because the laundry will be there anyway.

Thank you very much for your contribution already.

I don't like the space for the kitchen. Square kitchen spaces are generally very difficult to furnish. I also think the space is wasted, as there is also empty space towards the dining table. Unfortunately, I can't come up with a solution spontaneously without throwing the entire floor plan overboard.

We actually like to have a little space / play area for the children... and we don't want to fill everything up too much... maybe

here is a picture, maybe the kitchen itself will be planned about 0.5 m less towards the dining room

You can skip the door from the garage to the utility room, because if you drive the car in there, you would be blocking it right away.

Is the balcony or roof terrace really used, or is it, like in many cases, a nice but useless addition because you prefer to be in the garden?

Small wardrobe.

Personally, I would miss an extra room for office, hobby, sports, ...

Will there be an attic space?

Furnish the living room and kitchen properly with furniture.

Garage, as mentioned, will probably not be used for driving the car in, but rather as a storage room....

The balcony is used rather little, but we don’t like it visually from the outside as a flat roof, and as living space it is too expensive for us for a bedroom etc.

There will be very little attic space with this roof design..

Where is the street? Also in the south? Tell me, why an east garden? Or think about it yourself. It's probably a bit too much house for the budget.... Attention! I would expect to also want to sit in the entrance area in the evening. I would probably swap the kitchen and living room so that the kitchen is closer to the main dining terrace. But be careful: the design might have to be reduced... then many things no longer work. Everything works if it's large. You currently have 200 sqm... it probably has to be reduced to 130/140. What should be included in 280,000 or what is not included? For a shell house with packages that is probably about right... The guest WC also seems to be just a filler for a too-large house... I would never place it in the middle of a house... if there's a clog, everything might have to be dug up. I would say: little planning on huge size!

Corner lot, the street is to the south and west … the west is planned as the entrance (it could also be in the south, but this is not very sensible with our plot or this floor plan, because then in the rooms where we will spend most of our time we would be looking at the neighbor’s garage and we wouldn’t be able to utilize the width of the lot with boundary development...

So the budget is okay, we have 2 serious turnkey offers for a solid house KFW 55 KS panel elements.

Swapping the kitchen with the living room is possibly an idea, but I don’t know, if you sometimes don’t want visitors and want to “hide” in the living room, you sit directly at the entrance wall and can be seen through the window if the roller shutters are up.

Regarding the offers. Check everywhere it says bauseits. Look around here at the finances. There are hidden costs that no one talks about. Great for builders. Then look closely at the construction service description. Does the offered standard suffice for you? What does it cost extra to convert the balcony into living space? The rooms on the upper floor are quite spacious; there could be another room there. Consider a sliding door on the ground floor. There is no alternative room. Building services for connections, building services? Laundry, storage room is quite small, ironing certainly won't be done there.