2 full floors are not possible due to the development plan. Space-saving spiral staircases are planned as stairs to the attic - but that is still in the very distant future.
If that is not possible, then you should definitely reconsider the floor plan, especially on the upper floor. The architects in the other forum have already thoroughly dissected the floor plan. In this case, you don't even need to be an architect to see the major blunders.
By the way, the large windows in the small children's rooms do not make furnishing any easier.
Why is the bathroom on the upper floor planned to be so large? Don’t you have a basement where you can put the washing machine, dryer, and so on? This could increase the living space. I also find the kitchen on the ground floor too big. But everyone has their own priorities. For me, a larger living room and bedroom are more important than a big kitchen or bathroom. What I would definitely consider is the stair area. I would leave enough space for a stairlift. This secures you for the future.