To avoid additional construction costs and later trouble with many drains, the bathrooms should be planned on top of each other. The toilets as close on top of each other as possible. One can build differently, but the former simpler variant is simply more sensible. 250,000 for a 170 sqm city villa is not much, 50,000 for incidental construction costs including demolition is not much either. There should be a bit more straightforwardness in the exterior walls, simpler views without bay windows. I cannot assess your EL.
The slope’s course would be interesting here. I would possibly integrate the villa into the terrain and place the utility rooms there. You have too little storage space in the design!!! I would set up a utility room upstairs. The attic won’t be one, a cost-effective roof construction will ensure that. An attic with a floor hatch is also not suitable for storing items of use and consumption -> tools, decorations, crafts stuff, change/sports clothes, brooms, ironing board and so on. Maybe suitcases can be stored there...
If the balcony is added later for cost reasons, it can be used as a laundry balcony. Otherwise, it is superfluous with a garden, unless one of you smokes after getting up [emoji6] For the beds it may be useful, but it is utility versus cost [emoji20]