Floor plan, please provide tips and suggestions, single-family house 160m²

I can only agree with the previous speakers.
Front door opens the wrong way. The staircase in the entrance/dirty area might still work for you now, but with children running in and out several times with friends and running up and down, the dirt will spread throughout the entire upper floor and the (wooden) stairs will get pretty scratched up.
The WC feels cramped. Maybe add a few centimeters so you don’t constantly bump into the sink.
We have a 12 sqm utility room for technology, washing machine, dryer, dirty laundry, drying rack, and sports bags. That room is full. We also have a pantry (4.5 sqm) and a broom closet (2 sqm) additionally on the ground floor. Just like a double garage. And upstairs a built-in wardrobe (2 sqm) and in the attic a small storage room (12 sqm). Where is all your stuff supposed to go? Especially if children are still being planned?
For us, Maxi-Cosi, stroller, and baby clothes (to keep for the next one) are no longer needed because our family planning is complete and the youngest will be 3 when we move in. Don’t underestimate what all needs to be stored/put away. You really have zero alternatives.
What about cleaning supplies, Christmas decorations, etc.?
Otherwise, I would also place the couch against the interior wall and the TV in the southwest corner. Then you can look into the garden and you’re not sitting on display in the middle of the room. Then you could also place a door to the terrace if the dining table blocks the other one.
Upstairs, the bedroom seems very large plus an additional dressing room. Maybe better to convert this into a storage room.
Also, in the hallway next to the bathroom, another storage room could be created. Otherwise, I would also swap the children’s and parents’ rooms, as well as the bathroom.

The doors are not final yet and the front door is incorrectly drawn.

You mean the additional storage space on the upper floor between the stairs and the bathroom? Won't it feel too cramped up there then?
I don't think an additional room on the upper floor between the bathroom and the master bedroom would fit well. Especially since the doors would then again be in the corners of the rooms…

If the utility room still seems too small: We still have an approximately 18m² room in the garage and about 50m² of attic space.

Again regarding the dirty stairwell:
I took a look at your floor plan milkie and your stairs are also located in the dirty area, right?

As Manu suggested, we tried to see if we could make the utility room bigger.
You can find the result attached.
VERY IMPORTANT: We only did this quickly and only with a free program! So please don’t be too critical.

There is now a door in the utility room leading to the extra room in the attached garage.

Also, the problem with the stairs in front of the kids’ room upstairs is solved, they are now in front of the bathroom. And we can still move that door further south (upwards).

Thanks already to everyone for the important tips, especially about the falling child and the possibly too small utility room!

Our staircase is 2.5m away from the front door - directly opposite. The wardrobe is located to the right of the front door, meaning the area around the staircase is not entered with street shoes. But with you, everyone has to go through there directly. You can build it like that, but everyone with experience advises against it.

Regarding the upstairs, I meant that the dressing room can function as a storage room since the bedroom is very large. When the children leave the house, it can still be used as a dressing room if needed.