Floor plan optimization single-family house approx. 150 sqm - on a small plot

In the living area, no shelves/chest of drawers etc. are drawn by the architect where folders would go. Generally very little storage space. The utility room is used for technology and possibly stroller, laundry, and such. Where should decoration stuff and things like that go?

I understand your concern about planning too large. But I also see many carports and garages full to the brim in many new housing areas. Cars then stand in the yard or on the street. Think briefly about what kind of storage space you need in your apartment and where it should go in the future. Mentally cross out the utility room; it is full.

It doesn't have to be an office, maybe you can still find space somewhere for a desk corner. Somewhere you have to put binders, printer and such things, but you don't need a whole room for that. For many, this room probably also partially replaces a storage room.

For the size of the bathroom, I don't see any compelling reasons - you could easily move the wall on the right about 40 cm to the left without any kind of losses. For that, a built-in wardrobe left of the bed would fit in the bedroom. You could probably still use this as storage space on the upper floor.

The pantry is rubbish. Nothing fits in and it eats up space. I would rather enlarge the kitchen by that room and plan a direct access to the kitchen there.

I find the point about the office important. I would never have thought at my employer that I would do extensive home office. Now it seems to be going very quickly in a sustainable way that HO will also be possible after Corona. I wouldn't completely overlook this point. You have no space at all for organizing things like insurance and other documents.

In the living area, the architect has not indicated any shelves/dressers etc. where binders would go. Generally, very little storage space. The utility room is used for technology and possibly stroller, laundry and such. Where should decoration stuff and things like that go?

I understand your concern about planning too big. But I also see packed carports and garages in many new housing developments. Cars then stand in the yard or on the street. Think briefly about what kind of storage you need in your apartment and where it should go in the future. Mentally strike out the utility room, it’s full.

Currently, all my folders are in a sideboard. And I admit, we don’t even have a printer ops:

There is also some storage space being created under the roof, for suitcases and possibly a few boxes?

I actually find the floor plan quite good, except for the pantry... I would actually remove it completely and make the kitchen bigger instead.

Sure, you don’t have an office... You need to think about that again carefully. That’s always the issue when you don’t have a basement and the technical room has to be on the ground floor. I always find that very difficult!

The staircase has to be like that, or maybe a quarter-turn? That way you could get more square meters out of the individual rooms. You have a perfect wardrobe and a mega big hallway, which in my opinion is way too large.

The kitchen without the pantry is huge, I think that's very good. Also, the living-dining area is nice. But as I said... Because of the missing basement and "only" 150m², which definitely is not little, in my opinion you’re missing a room on the ground floor.

I could imagine that with a suitable quarter-turn staircase, a small office room could be created... You’d have to draw it and try it out.

Just draw the actual furniture to scale in every room. The ones you have and the ones you would buy.

I would delete the pantry.
I don’t like the bedroom upstairs. Because of the windows, the bed is so squeezed into the corner.

You have 2 rooms that can be used flexibly. Dressing room and second children’s room. If you don’t get a second child, the dressing room stays a dressing room and child 2 becomes guest/office. If there is a second child, a small workstation can go in the dressing room. I would design the bedroom so that a large wardrobe fits and the dressing room can be repurposed.
Also the comment from 11ant. I prefer children’s rooms of equal size but for an age difference of 10+ they can definitely be different sizes.

Design the hallway below with a big door to the living area, so that with a large group or if you need more play area for child 2, the space can be shared.

That’s okay. Just keep in mind, for example, during parental leave of child 2, that formalities do arise and they can’t just be printed sort of semi-illegally at work. I don’t see a sideboard sketched in the floor plan right now.

Please ask your general contractor for a fully dimensioned drawing and use millimeter paper to plan in your current or desired furniture. That was very insightful for us in the design phase. Whether it works out in practice remains to be seen.

Regarding storage space in the attic for insurance documents, etc., I would put a big question mark. That would not suit my “order” at all. I would then have a huge pile of paper somewhere that gets sorted every 3 years. For your pile of paper, the kitchen is the only suitable place. You can do that, I could live with that; my wife would go crazy.