Floor plan of a single-family house approx. 160m², hipped roof, with basement, hillside location

From the street, it looks like a bungalow, you enter there, upstairs are the bedrooms, stairs down to the living room with terrace. In the slope itself then [TK] and utility room...

Ah, ok... so the architect had nothing to do with it, and the staircase is where it is because of the inflation. I can sketch something later showing what a hillside house would look like... unless you say you want it exactly like that and really like balconies and basements..

Yes, it would definitely be interesting for us to see. We actually didn't find the whole thing terribly bad so far... which of course doesn't mean that everything has to be exactly like that. As we were told, we can't do much more regarding the building envelope based on the exterior dimensions. That's why the basement was also planned as it is now. If necessary, one would have to follow up on that again.

Sloping sites are naturally problematic in the sense that, as far as I know, there are no show home centers with sloping plots. Therefore, the builder can only inevitably fall in love with slab-on-ground houses at the exhibitions. The question "what can be improved in this design?" can thus only be answered with "nothing, it has to be replaced." Because any other answer would be "woulda, coulda, shoulda" if you don’t have the suitable slab-on-ground plot. A sloping plot needs a hillside house - not a slab-on-ground house supported by a basement.

From the street it then looks like a bungalow, you enter there, upstairs are the bedrooms, stairs down to the all-purpose room with terrace. In the slope itself then the TK and utility room...

TK and utility room might also be located under the garage. I would pull the carport forward towards the street, then add a storage area behind it. But without the details of the textual version of the development plan, it is simply not possible to help.

Is there a plan with height specifications? The street is probably about 1 m higher than the terrain, right? What is the reference point for the height? What does the development plan say?

Developers usually do not manage construction sites with architects. Just say who is on the plan stamp. I am looking for capable architects who have knowledge about building on slopes.

Unfortunately, I do not currently have the plan available, but it does exist; I will have to request it again. The street transitions into the terrain without a significant step (see attached image, it should be recognizable there). I have only roughly estimated the slope.

Ground floor underfloor heating 252.7m then basement underfloor heating 249.7m. That is how you build on a slope. Unless you absolutely want to have a basement and pay for it.

Our plan was not specifically to have a basement. Due to the space we wanted (hobby room + future office in the basement), according to the company, it was not feasible on 2 levels. If that should not be true, we do not necessarily need a basement.

And to be honest, I am surprised why the design is received so negatively. What are the underlying reasons that everyone sees what is planned here as such a big disaster? I do not really understand that yet. What do I gain if I plan the mentioned slope house with 2 instead of 3 levels? Sorry for being stupid, but I am posting here to learn something.

Something like that.
You’ll have to chamfer anyway, that’s already factored into the exorbitant incidental building costs...
The program can’t display everything: I used your plot as a template. The house is set forward and narrower, but also wider up to 3 meters to the boundary. I haven’t really planned the basement much, but just quickly indicated where utility rooms and living areas could be. The garage is basemented as living space up to the 3 meters. Overall, you save the entire utility basement, but it still comes to about 160 sqm... okay, some brainwork is required since I only quickly included 10 cm walls.