Attach to property access planning

And if I understand the OP correctly, the main contractor does not want to start deeper because as a timber construction main contractor he only wants to purchase the basement and not also the first residential floor above

The main contractor will have to accept that if he wants the contract. With such projects, individual contracting is apparently significantly more flexible.

I am afraid the OP tends towards inclusive planning by the general contractor. However, I do not see a service yard property here :-(

We have 1.2 m over 8 m in length. Slightly steeper than in Hampshire. My parents have a piece with 2 m over 6 m in length. Doable without ice and snow. However, in winter you often end up sitting on your bottom involuntarily. Regardless of what the structural engineer says, at least the parts in contact with the ground are made of concrete. Definitely plan the outdoor area as well. Stairs, terraces, retaining walls

clearly shows an integrated garage on the mountain side as well

Whether the garage is integrated cannot be answered with certainty due to the missing third dimension, since one cannot assume a usual true straight section with a system section. In any case, the garage is located below the basement and does not extend the full depth of the house. Here is an "underground garage" with visitor parking spaces in front.

:
Thank you very much for your suggestion, I know that we have to do earthworks, but I have no interest in redesigning almost the entire property.

At the moment, we are still puzzled about how to realize the whole thing and, above all, to implement it affordably.

Regards, Anson

Currently we are still faced with a puzzle of how to realize the whole thing and above all implement it affordably.

Very affordable because free would be statements regarding inquiries such as the constellation between the concrete worker and the carpenter and your connection to the breadwinner of the draftsman - we can then gladly contribute to solving the puzzles.