Variants for furnishing the all-purpose room

uh we pay 50 euros from 7 to 16:30 100 euros are covered by the Freistaat before that it was 150 and daycare was, I think, 170 without lunch

That's a bargain, you lucky one ;)

You don’t need 2 bathrooms on the upper floor. Even if the parents sleep upstairs, especially only temporarily. By the time the kids use a kids’ bathroom, they are older and either you or the teenager is downstairs. I would plan the ground floor anew.

Then it is basically what it is now. Remove the wall between the bedroom and the dressing room, and you have a flexible room. A study or a room with two possible working areas. Or a children’s room or parents’ area or whatever.

It is an experiment with sleeping downstairs. Assuming that children live at home possibly even during university, the period in which the concept fits is longer than the period in which there could be problems (until toddler age). And as I said: moving the bedroom upstairs would be feasible without any problem. Then there would only be the master bathroom downstairs, like a typical shower bathroom on the ground floor.

For daycare you pay, for example, 600-700€...

From 0-3, but not the normal kindergarten 3-6, right? And it continues with moving walls, rearranging furniture, etc.

Then basically it is what it is now. Remove the wall between the bedroom and the dressing room, and you already have a flexible room. A study or a room with two possible work areas. Or a children's room or parents' area or whatever.

Still, the room downstairs will not become more optimal. You should really take another look at it. Maybe the student will also move downstairs. So you don't wake up when the youngsters put pizza in the oven and chat at 3 a.m.

If the ground floor bedroom has to be that small, then I would consider installing a sliding door as the door to the dressing room. This at least avoids the problem that the 90 cm door reaches up to the bed and blocks walkways.