Ground floor and basement with bedrooms and bathroom in the basement - what do you think about the planning?

Then living upstairs fits. Living belongs to the garden The plan is way too big. You have well over 140 sqm. Much more. We have 11x11m 2VG like you and come to 190 sqm of living and usable space. Take a look at town villas of that size. They are 9.5 x 9.5 m It may be that you have to be a bit bigger because of the slope, since not all sides have windows.

Would you like to include a window in the (separate) shower room? I find windows especially pleasant in small rooms where a lot of water vapor is generated. Unless it is a sauna.

I would make sure that the children's room gets a lot of light. In the middle of the basement, there is only a side window, how is the slope there, how big can the window be? Possibly swap with the parents' area. The child lives in the room, does homework there, etc., and needs light, while the parents only go there to sleep. Windows on 2 sides, even if one of them is north, bring a brighter living feel to the room. Larger windows may also be possible on the northeast corner due to the slope of the ground.