But one more question. The draftsman of the general contractor always said that because it is a 36.5 cm masonry, it is not so bad. Is that really the case or did he just want me to leave him alone?
I suspect you yourself did not quite understand it yet and he noticed that too (?) - what that is supposed to have to do with the wall thickness in his opinion is beyond me. Besides, this also applies to the interior walls.
Can you take another look at my ceiling opening for the stairs? (hole) At first glance, it looks too big to me.
I can't see what would be too big there. Of course, I noticed that the stairs end at the exit with only a half-deep step, and according to the drawing, they also hover in front of the edge of their ceiling opening. But the sanitary fixtures also hover, and I don't recall seeing a section (?) - so I suspect a drawing oversight and hope the general contractor has a well-coordinated shell construction team who already knows the draftsman's notation and is not confused by it. By the way, I also don't see the rise dimension noted, and the rises have to be counted manually. By the way, with my master craftsman, the draftsman was an experienced assistant and also did site management - he would never have drawn anything that would have forced the executors to improvise in practice. Nowadays, there are digital natives working who cannot understand the practice precisely because of its analog nature.