Thank you for the opportunity to work on your project. I enjoyed working on it and hope you'll find the proposal equally satisfying.
My main focus for the project was to make a functional layout that meets all your needs and requirements beautifully. The layout is partially shaped by the structure of the building, plumbing installations, and the window layout, and therefore there are some constraints on what is possible and what is an optimal solution.
You did mention that it could be possible to change the window sizes and positions, but since it's an apartment and not a private house this is likely not a good idea for the architecture and design of the overall building and for you privately probably not worth the hassle.
The overall layout is changed significantly compared to the current state of the apartment without making changes to the building facade or the plumbing system.
I'll briefly talk you through the proposal room by room.
As you enter the apartment you walk into a large entrance hall with an open view of the dining area. The entrance hall has a small seating area and a built-in wardrobe for daily outwear and guest coats.
This area is in my opinion quite wide and what I would suggest if you have the possibility to close one of the entrance doors from the inside, the boys' bedroom could be extended towards the corridor and more storage space could be placed in the hallway. The room would become around 6-7 sqm larger. I haven't done this since I was uncertain if it's something that you would like to do.
The living area is now facing east and north. It consists of a lounge area with a large sofa and lounge chairs, a large dining area for 6-10 people, and a kitchen with the flexibility to be open or closed toward the living area.
The kitchen is linear, fully equipped with lots of natural light and a small breakfast nook/bar towards the lounge. It uses the existing installations from the current large bathroom.
The master bedroom is placed in the current lounge area. This decision was made due to natural light and the overall dimensions of the space. On the west side by the elevator, the space is more narrow and has less natural sunlight. This is the reason I've moved the lounge to a more open space that is more welcoming and placed the study and gym area in this space, directly connected to the master bedroom.
The master bedroom has a large walk-in wardrobe, large double bed, vanity corner, and tv mounted on the divider between the study and the bedroom. The bedroom, like all the other bedrooms, has its own en-suite bathroom with a large double walk-in shower, double sink, toilet, and bidet.
The shared bathroom is directly accessible from the entrance hall and is equipped with a large double sink, shower, toilet, and bidet. The toilets from this bathroom and the master bedroom bathroom are placed on the same wall to be able to use the same outlet on the north wall.
On the south side of the apartment are both kids' bedrooms with bathrooms. The boys' room is the one on the west side with the possibility to be enlarged and the girls' bedroom on the east side. This can be switched if it's something you prefer. Since the design of children's rooms requires little more info and insight into how they spend their time, I've got a vision of how it could be organized but would be happy to further consult with you on this if you like the overall direction of the project. Therefore, I haven't rendered these spaces as detailed as the living area and master bedroom.
The laundry is also accessed from the entrance hall but uses the plumbing on the south side of the apartment.
I hope you like the proposal, and if you have any further questions or need additional drawings of some part of the proposal feel free to contact me.