We want to build - decision support floor plan

Hello everyone,
to briefly introduce ourselves, we are a small family from MV and want to build in the Rostock area. I came across this forum by chance and find your opinions on various topics very interesting. Now about us:
We have about 6.50 sqm of land and have decided on a 1.5-story solid construction. (Aktionshaus) DIN 277 106.5, living space 95.5.
We are still undecided about the choice of sqm, as the rooms upstairs appear very small, although the knee wall is 1.33 and only then does the slope begin. Floor plan attached.
We are satisfied with the size of the rooms in the basement. The considerations regarding the upper floor. The bedroom is only 2.70 deep. We have thought about changing the design of the rooms, possibly moving walls?
Attached is an example.
Should we perhaps decide on a bigger house after all? If I am not mistaken, the house would then be 1 meter longer. But would that really change anything?
Thank you and best regards

Shifting the walls on the upper floor in favor of the children's room is commendable. But where do you want to store your clothes then? Under the bed? That leaves zero space for a wardrobe.

The question shouldn't be whether you should build bigger. Rather, whether you want to and can afford to build bigger.

My opinion on that?

95.5m² is definitely not meant for 4 people. It already starts in the utility room downstairs. It is much, much, much too small.
A large electrical box, the heating, water and gas connections, heating circuit distributor, the washing machine, and possibly the dryer are supposed to go in there?
Never ever. There is simply not that much floor space and wall space.
Our kitchen is already quite small at 9,x m², but it just about works. At 7m² you just stand on each other's toes.
The living room is the only spacious room in the house, although the fireplace probably won’t really find a proper place there either.
If it’s a matter of money, then get rid of the fireplace and make the house at least 120-125m², then it will also work upstairs.

What purpose should the house serve? 2 people? 3? 4? For 2 people, the children's room could serve as a dressing room. For 4 people, it will be tight.

The architect of our BU said that a children's room can only be called that if it is at least 10 - 12 sqm in size. Otherwise, it would be considered a guest room.

The children's rooms in our house are certainly not spacious, as we needed three children's rooms. But they have a floor area of 14 sqm, minus the slope (1.60m knee wall), which gives us a calculated 12.5 sqm. And that's just enough for all the toys, the bed, wardrobe, and shelves.

Barely 3.5 sqm for the HAR???? Never!!!! We have 12.5 sqm and there, besides the hot water storage tank, the buffer storage tank, the controlled residential ventilation, the electrical panel, and the utility connections, we only have space left for a freezer, a shoe cabinet (50 cm), and the washing machine and dryer.
There is no more room. For all the small stuff, we have hung shelves.

You pay so much money for a house and end up with less living/storage space than in a rental apartment with a basement..