Which floor plan to choose for a 145 sqm flat roof? Ideas?

Hello,
we want to build a flat roof house of 145 sqm. We have two floor plans but cannot decide.
Background information:
Due to the building window, the front door must be at the front of the house. The garden is facing south. The kitchen is in the southwest.
We have one child and definitely want a second. A third child is possible. We do not want to decide yet, so we definitely need a third children's room/office.
Which of the two floor plans would you prefer? Tips/suggestions for improvement for the ground floor/upper floor are welcome!!!
The main difference is the staircase and the resulting changes.
Thank you

Where is the 3rd children's room/office in the 1st floor plan?

...therefore we definitely need a third children's room/office.

Maybe I overlooked something - but under that premise, it's quite simple: the first one is out.

Oops, my mistake. In the first floor plan, the bathroom goes into the dressing room on the upper floor and the "office" goes into the bathroom. The walls will be slightly moved so that the bathroom is about 9 sqm.

We have two floor plans, but we cannot decide.

Two "floor plans"? - it seems to me they come from two providers, which puts the question on a whole different level?

Both providers can realize both floor plans.