Floor plan single-family house 190m2 with basement. Feedback?

Here's an example of how a classic split fits on your property:

That clearly illustrates the clever use of the slope. Although a split-level house itself is not to everyone's taste if you have to walk half stairs to almost every room. That's why my suggestion to you. Simply set the house about 5m away from the street about 0.5m higher and then have a proper full living floor below and the bedrooms above. Then you have a good sense of space and no annoying stairs.

That already clearly illustrates the clever use of the slope. Although a split-level house is not everyone's cup of tea, ...

Yes, I had already mentioned that. But one has to say that there are split-level houses and split-level houses. Good architects turn split plots into fantastic living worlds, where some others wish they had more or less of a slope to be able to build it the same way. But that's certainly also a question of money. ;) What was especially important to me here was to make clear to the OP what options he has and that he first has to deal with his slope before adapting the floor plan to it. I interpret the ongoing silence as "message received."

Here is a visualization. I would go with option 3, so move/drive slightly upward to get to the ground floor. With option 1, you basically have your balcony again, even if it is not on stilts but on the ground. I think cellarizing the garage is the ideal solution. Then you only need 2 floors and can orient the living room, dining room, and kitchen broadly towards the south. The garage just must not be a boundary building.

Just a sketch, which unfortunately I cannot share. However, the terrain slope is relatively straight from 4.8m at the street to 0m on the south side. The west side runs about 0.3m below the east side.

The basement is included in the 650 k€, for the outdoor facilities and other ancillary building costs we have allocated 72 k€. Unfortunately, we have not yet found a good way to substantiate this figure. Do you have a suggestion?

We also placed a house on a slope mostly according to our own planning: 4m height difference over 32m plot depth.
The financial result (also due to various retaining walls) was 30% additional costs on the turnkey price until the interior finishing was completed and the outdoor facilities were in place. (Planting, of course, not included)
In the case of the OP, one could therefore expect about €220,000 in ancillary costs.
Special features like the embankment of a terrace or garage were not included in our case, as our plot rises from the street upwards. We also do not have a garage; it fell victim to the additional costs.

Just picked out and as examples: It is simply great how wonderfully a stranger is helped in the forum. I would be interested in the number of builders who have completely or partially revamped their house because of this.