Screed - incorrect height - how to fix?

Can be connected very well with a rail. It is similar for us. In the bedroom, [KZ] and office vinyl, everywhere else tiles. The transition from the hallway to the bedroom receives an aluminum rail designed for this purpose.

You will then have a 4mm difference, as the parquet screed is 2mm higher than the target and the parquet itself is 2mm higher than the tile. However, 4mm is not a big deal. The transition will be tapered. If necessary, the tile screed can also be corrected with flow screed or the adhesive can be applied a bit thicker. The former is used in renovations.

However, you will then have a 4mm difference, since the parquet screed is 2mm higher than the intended height and the parquet itself 2mm higher than the tile.
However, 4mm is not a big deal. The transition will be filled in. If necessary, the tile screed can also be corrected with flowing screed or the adhesive can be applied a bit thicker. The former is used in renovations.

Yes exactly, that was what was causing me some headaches.
The problem is that actually all transitions wouldn’t fit because it is the hallway that is affected. That means transitions to kitchen/dining/living, study, bathroom and wardrobe. Quite a lot would have to be corrected there.
Yesterday we briefly had our tiler here, who said he wouldn’t accept it as it is because at the stair opening a steel strip is mounted as a finishing trim at the ceiling between basement and ground floor (hope it’s clear what I mean) and the floor covering would then protrude here since it is 4 mm too high. So filling in the rest of the area is definitely out of the question.
We have now been assigned a representative for our site manager and hopefully will be able to clarify this soon.

You can connect very well with a rail. It is similar with us. In the bedroom, KZ and office vinyl, everywhere else tiles. The transition from the hallway to the bedroom gets an aluminum rail designed for that.

We definitely wanted a transition without a rail, just with a joint, so that is out of the question.

and the flooring would then protrude here because it is 4 mm too high.

I don't understand that. The staircase is in the hallway… and in the hallway, the screed is now 2 mm too low at the staircase (not at the parquet of the other rooms). You can just level that to the staircase, right?! Where do you have parquet/tiles everywhere? According to my understanding of a standard floor plan, the transition hallway/living area with 4mm, hallway/staircase with 2mm could be affected. The hallway is always 2mm lower than planned. Show me on a plan where exactly 2mm are missing or too much.

I don't understand that. The stairs are in the hallway… and in the hallway the screed by the stairs (not by the parquet of the other rooms) is now 2 mm too low. You can just level that up to the stairs, can't you?! Where do you have parquet/tiles everywhere? In my understanding of a standard floor plan, the transition hallway/living area with 4mm, hallway/stairs with 2mm should be affected. The hallway is always 2mm lower than planned. Show it on a plan where exactly 2mm are missing or too much.

The hallway is 2 mm too high. The wardrobe at the entrance is 2 mm too low, but that is the smaller problem. I will try to sketch it later.