Additional insulation in the Ytong basement (36 cm)

I can hardly imagine that Ytongg® would recommend that you do without perimeter insulation in a partially underground residential basement - or better said, in your case, a lower ground floor (LGF).

..that's exactly how I see it too ... if there is no adequate ventilation and exhaust of the living spaces in the basement floor to regulate the moisture content in the room, then mold growth is already programmed ..

We are on the slope and have no pressing water

.. but surface water in the "broken ground" can very quickly turn into pressing water ..

What is a YTONG basement?