@ Dr. Hix
probably sloppily formulated. The insulation is directly on the OSB board with us (there is no masonry) or to put it more precisely, the insulation layer is directly on the other insulation layers of the outer wall. Then the 3 cm air gap and on top of that the wooden cladding.
Regarding the "merely plastering instead of elaborately cladding," I have to object that I consider plastering to be much more difficult and complicated. At least if you want to achieve a decent appearance as an amateur. Staining the wooden slats, applying black tongue and groove, and screwing them on was really extremely easy and the whole thing, with about 20 euros per square meter just for the wood, was also affordable in terms of price.
At the bottom is Neopor and plaster and it looks so hideously ugly, what the "experts" have done there, that I decided to "apply brick slips" (again with a method friendly to amateurs, I am fed up with craftsmen and their "skills" for now).