Drywall partition + door self-commission or through construction company

Hello everyone,

We are currently having a semi-detached house built and are building through a general contractor who will hand over the house to us turnkey in the end.
Now the developer is offering an adjustment option, where an additional wall will be built in the bedroom and another door will be installed. This would turn one room into two. These works would include the installation of a single-planked drywall partition + materials and the installation of a door in another drywall partition. A price of €5,100 is being charged for this effort.

Now my question:
Is this a fair price or should this work be done later by an independent craftsman/trade company?
Questions regarding later liability, material procurement, etc. should also be taken into consideration.

Here are some more detailed data:
The wall will have an area of 2.743m x 4.225m. The door consists of a wooden frame and a hollow chamber core door in smooth white with square edges with a height of 2.13m.

Thanks in advance,
shirocko

The price is proud. Who is doing the flooring?

Does your GU build the drywall on the screed or first the wall and then the screed? Afterwards, it is only possible on the screed. Which rooms does the wall separate?

Insanity. No wonder why construction is so expensive. We have just converted an entire attic ourselves using drywall elements. A simple drywall wall with door installation should be a 3/4 day job for professionals, if at all. To put the material costs into perspective: when we started, we ordered a flat rate of 100sqm of drywall, 100sqm of OSB (15mm), and about 150m of drywall profiles. In addition, about 40 kg of filler and 5,000 drywall screws. We paid €1,680 for it. Of course, the door is extra, but maybe this helps to put the material costs of the [GU] into perspective. At that price, I would take it into my own hands.

The price is proud. Who is doing the flooring?

The flooring is done by the general contractor as standard.

Does your GC build the drywall on the screed or the wall first and then the screed? Retrofitting is only possible on the screed.

Which rooms does the wall separate?

Unfortunately, I cannot say anything about the exact order of execution yet, but I assume that the drywall is installed on the screed.
The wall would divide the bedroom into 2 rooms.
Attached is a picture of the variant.

Variant without extra wall:

Variant with extra wall:

The question is whether you then have to do drywall and flooring and if the flooring will also be calculated for you. If not, you have to include the flooring in your calculations.