The first thing I noticed is that the dining table is placed with the head side towards the bench. In my opinion, that only wastes space and looks illogical.
The technical room is really quite small. Do you really need the shower on the ground floor? You could fit some more equipment there.
I think the ratio of the children's room size to the bedroom size is great. The children live in their rooms. Only the parents sleep in the bedroom. You don't really need more space in the bedroom, and if you like it a bit cozy, this is just right. A bit of discipline with the amount of clothing, and that's it.
The gallery upstairs is useful—as long as it is closed off—as a storage room and "upstairs wardrobe." The wardrobe space downstairs forces discipline: everyone only one jacket and one pair of shoes...
A study room is important if it is regularly used for value creation. I would reserve part of the wardrobe in the study room for out-of-season clothes that are not needed.
There is too little space for a stroller—but given the children's ages, this is a temporary phase that can be quickly bridged; I wouldn't plan for more.
You don't have to make everything "large," and if an area is "tight like in an apartment" (as was described, among other things), that is not necessarily a disadvantage.