Single-family house with a ground-level granny flat on a slope

I would divide the terrace/outdoor area into 3 independent sections Family/Community/Parents-in-law Take a look at the thread by Granny flat for parents Slope location similar to yours just without the access problem

... and above all: no hip roof!

Okaaaay, no hip roof we can also imagine a shed roof - the main thing is that I am allowed the hip roof

I am now very happy with the access. Now I just need a surveyor and an architect to roughly plan the house with the heights.

The issue of privacy can easily be addressed with a partition wall

I cannot write anything about architects. However, there is a thread about construction companies around Heilbronn. Surely, some of them have also built on the slope. I would simply enter Heilbronn in the search function.

EDIT: A partition wall only provides visual privacy because you can still hear everything. It wouldn't be for me.

Thank you very much, I will do that. The matter of privacy is acceptable to us as something desirable.

The thing with privacy is acceptable for us as it is desirable.

Partition... o_O whose parents are they? Yours! That will only cause trouble in the long run... but you are adults.