House placement on a slight slope, tips?

... but as you can see it is not a 1:1 match to your situation, since we were allowed to build "almost" 3 floors - so the question of how we distribute between the upper floor and ground floor did not really arise, we simply added a basement. However, maybe your development plan (& budget) also allow such a configuration, as long as you are sufficiently "buried" with the basement?

The garage is also on our property boundary and at the same time serves as a side exit to the garden - it was difficult to get approval for this, as it is basically not allowed as a boundary building (it is basically a roof terrace), but since we (hopefully) designed everything nicely as a roof garden area, it was approved.

North is at the top of the plan

Sorry, that was clear to me.

All good. However, the sketch confuses more than it helps. How is the slope distributed? Is the gradient even or does the plot rise at the back? How is the slope at the building plot? It’s best if you sketch it out: 20 x 26, after 5 meters the building boundary, and then the heights. With the almost south-facing position, the slope plays a rather minor role in terms of orientation.

Your choice of words is somewhat unfortunate.

Build the house as far back as possible and into the slope, large front garden?
House towards the front and the living spaces upwards/towards the street? Living room downstairs in the dark half-basement?
Excavate everything and then look out onto retaining walls at the back?

Does the plot now rise from the street, approximately northwest, 3 m towards southeast? Therefore plan with measurements and contour lines.

The map is from the Geoportal. Isn't there an option to display the contour lines?

Without specifications from the development plan and heights, no further assistance can be provided here.

According to your information, there is a 13% slope towards the street.

I have bought a plot of land and am a bit helpless about how to position the house.

And I am normally someone who likes to help. But if your hands are tied while helping, you prefer to move on to the next patient – who may be bleeding less severely but cooperates better. The fact that the crumbs thrown out by the questioners are unfortunately only seemingly clear and meaningful regularly happens with laypeople – then you quickly seek other sources to fill the basic gaps. With redacted clues, that cannot succeed. The only thing you left recognizable is Tannenstraße – but there are hundreds of those, I will definitely not search through them. In this respect, every OP is also the architect of their own misfortune ;-)