For me, such an entrance situation/driveway to the house would be a no-go in a free house planning. A house entrance does not necessarily have to look presidential, but here it seems rather forced to me and additionally directly on the driveway of the cars. never! 5.60m garage width with bicycles, screws, etc. for two cars is little. We have also raised children in the newly built house back then, but in your space requirements, in my opinion, the term "playing" appears extraordinarily often. Children will find their place and usually look for totally different places than the assigned ones anyway, and this kind of playing only takes place over a limited period. Whether I would create so much extra space for that at €3-3,500 per sqm... I don't know, especially if I might quickly run out of money elsewhere. In a really stylish house, you can easily hide €100-200,000 more permanently and sensibly at the same area. When the children become teenagers, they need exactly the opposite most of the time.
Generally, we would like the possibility to separate the upper floor, e.g. as a separate living unit in old age, which is not possible here. You would then have to work with an outside staircase.
As a multiple offender, I believe I read that you currently want to plan the jack of all trades, which is absolutely understandable for such a project. But you still have a while until "old age" and from my own experience and various others around me, I would rather discard the planning of a separable upper floor. No one wants to climb up such a chicken ladder at some point, and needs usually develop quite differently than you intend with it. I would find the idea more interesting to separate the children's area with its own shower/toilet from the rest of the house somewhat or possibly even the house entrance, for their own peace and privacy as well as for the young people. Currently, you do have a U, but it is pressed directly against the inside wall, an expensive, often unattractive sliding door solution without real sound reduction. First of all, (and I know this from some participants here) I would wish for a drawn sketch, especially with individual measurements, above all also with furniture dimensions of the then real! furniture. These floor plans from the PC look nice but are less suitable for deeper floor plan discussions. Floor plan: You have to walk around the front door to get to the stairs, which is not very comfortable. The start of the (why?) straight staircase is very close to the wall and does not create a nice room feeling and appears cramped. The ground floor shower is probably 140 cm and must then result in the disliked glass solution because the passage must already be about 70 cm; furthermore, the door almost hits the toilet that you approach directly... all this shows up when you draw in the real measurements. Apparently, the living room will mainly be a TV room, so I would consider whether it should even be there, especially since it should be acoustically separated as well. I once lived so that the living room was on the other side of the house, in a quiet room, and I found that nice for everyone. I don't mean a 1:1 exchange, but such an idea would give freedom in the dining/kitchen area and this living room could then be significantly smaller, while the all-purpose room without the living room would be larger. On the upper floor, I see that the drawn doors are probably not to scale either, so again, definitely draw precisely, also again furniture, TV wall, etc. The bathroom is huge with 13 sqm but not nicely designed; you don't need the bathtub to get a nice bathroom; the toilet there is far from the window and also cramped. The shower with 180 cm also does not suffice for the desired glass-free version. We have done it here with 140x90 plus passage width; you don't have that here. I would rather push the shower behind the toilet and move the toilet to the other side. The three children's rooms or extra rooms could be arranged differently so that each children's room has about 14 sqm. The middle one could perhaps also (in advance?) remain a nice, open area for old and young or then become the third room if needed; that could easily be prepared. This could become an exciting and constructive discussion here once again, which unfortunately is becoming less and less. I find it good that you also share your mental background because these are precisely necessary to be able to design a house really individually.