Screed has been in for three days and is still wet?

Also, doesn't everything look quite tidy from the photos? Do you have a bad trust relationship with your construction company? Otherwise, I would trust a bit more that they know what they are doing and when. After all, they are also responsible for the warranty of the place. The biggest fear I would probably have is mold if it’s still too wet. The screed should be load-bearing after 2 weeks.

If I had wanted to separate the toilet from the sink with a partial wall, for example, it would have had to be done before the screed. But we don’t have that at all. It’s about the cladding, so to speak.

And what do you think ... are drywall partitions installed before the screed somehow protected against moisture differently than drywall cladding applied later (in 2 or 3 rooms)? ;) ;) In my case, all drywall partitions (in a renovated old building) that were meant to be permanent were installed BEFORE the screed, including their cladding. And after about 14 days, my landlord started doing the rest of the drywall work. I have been living in this kind of renovated apartment without mold since 2011.

I would be much more annoyed about the window reveals. The lower one is supposed to be vertical, the upper one horizontal. This way, due to poorer circulation, you are more likely to get condensation on the window.

Oh dear... there's a lot of half-knowledge being thrown around here again. Drywall in the bathroom is done with wet room boards, which are much less affected by moisture from the screed than normal boards. Drywall on screed is completely normal, and in renovations of old buildings, it is often the most sensible option. This is also commonly done in office spaces because it allows flexibility in room usage. The profiles don't have to be screwed into the screed; they can also be glued.

Regarding the question of exactly when gypsum board molds, I abstain due to ignorance ;)

I honestly didn't think about weights at all.

You don't have to. The insulation material under the screed has a load-bearing capacity of 10t/m2. So you have to build something other than tiles and a washbasin on top.

Gypsum itself cannot mold. In case of drywall, the cardboard can of course mold but at the beginning it is still full of fungicides. Mold is actually not a problem for gypsum during the construction phase (unless it lasts very long). Later, when dust and other organic particles have settled, mold is of course also an issue under continuous moisture... Gypsum itself can also handle moisture very well. It is very absorbent and also dries quickly again (by the way better than lime cement). When you have dry phases. And that is the problem with drywall/plaster. Under continuous moisture it loses its stability. It can then really dissolve. That is inconvenient and also affects the load-bearing capacity in the long run. So if you say gypsum does not like too much moisture, you really mean the duration, less the amount (eventually that is also too much, but usually not in normal construction projects). That means, yes, if after the whole process dry phases occur, it is actually no problem. The question is what the painter paints with. If he uses dispersion paint the moisture could be trapped in the drywall and the dispersion is organic, so there is again a risk of mold. So drywall is probably okay, but I would only paint (or have it painted) after the functional (or even occupancy) heating. Good luck!