Building ground suddenly a biotope

not even from a city.

Even less so from a city. The people there generally know what they absolutely have to say and the rest doesn't matter to them because of the time involved. In private sales, there is still the hope that the other party (if they know about the matter) will say more rather than less to avoid any legal dispute... you will get rid of the property anyway.

Why don't you place the house as far as possible towards the southeast within the building plot?
The garage is marked at the bottom left, isn't it?
You don't have to force generating a south-facing garden that is too hot for 5 months of the year.

How do you say that nicely now. So our house is spatially oriented to the south kitchen dining room living room with large windows facing south. That is why so high up since we have been granted a 2 meter garden fence below, no one can really look inside. The place has between 200 and 300 inhabitants who are partly also very curious.

You can still rotate the house. 90 degrees and the south becomes west

No, we are not allowed to; the house must face the longer side parallel to the street.

Before you spend €50,000 on mitigation measures (check here first how much it really is), I would still consider alternatives like a new floor plan. Old construction prices or not, it won't be €50,000 more expensive. It rather sounds like a sales trick to rush you into signing as quickly as possible: "The offer is only valid today."

Don't make an expensive decision out of spite just because you don't like the answers here.