3m raw construction measurement is already little. I personally would take the 3.50m. That I would not want to sleep on the ground floor is just mentioned in passing ^^
Small children do not play alone in their rooms while one works. That only becomes relevant starting from school age – but then the children are at school while one works and not in the children's room. I would rather plan the bedroom upstairs right away. 3 m for the office is great and you are closer to the coffee machine.
One office is not enough, actually two would be needed. Room next to room with an open door, I consider it more likely that children feel safe in the children's room and like to play there if the parents are next door. We already sleep on the ground floor today and find it great.
3m shell construction measurement is already little. Personally, I would take the 3.50m. Just to mention in passing that I wouldn't want to sleep on the ground floor ^^
3.00m versus 3.50m is not the right comparison. The bed would be rotated. I think you can speak of finished dimensions here. The walls are sketched as 20cm thick, it won't be that even with plaster. But better to calculate a bit tighter, so that you have at least 3.00m in reality afterwards ;-)
The structure with the large open space is not good for the bedroom. The door swings right up against the bed. Maybe you would put up with that in a hotel in London, but certainly not in a newly planned single-family house.
3.00m to 3.50m is not the correct comparison. The bed would be turned. I think you can speak of a finished dimension here. The walls are sketched as 20cm thick, it won't be that even with plaster. But better to calculate a bit tighter so that you have at least 3.00m in reality afterwards ;-)