Planning of a classic single-family house with approx. 127 sqm

Yes, that is correct, I will adjust my calculation once again.

Turnkey does not equal ready to move in = materials for floors and painting, if at all, are provided through own work...

so at 2,000 € per sqm the house should already be completely finished

....that you are not mistaken there

That's why I'm asking here, but the current essence from many posts was an average cost planning of €2,000 per sqm for the finished house. So I mean various posts in the forum.

Schwörerhaus was at €2,500
Danwood was rather at €1,660

The middle ground would be enough... it shouldn't be the cheapest but also shouldn't become the most expensive

Property transfer tax will be lower because pure land costs are lower.

How do you mean that?