GU wishes construction supervision from DEKRA

We have hired TÜV, which is not cheap either, and so far we are satisfied. Of course, this is a subjective assessment.

Of course, this is a subjective assessment.

The other posts here as well, even if the wording intends to convey otherwise. In this respect, it's fine ;)

Hm thanks for the assessment. Why do you think an independent expert is more suitable than one from TÜV, DEKRA & Co.? The price expectation is a good point, the 5-phase test from TÜV, for example, costs about €3300. If you don’t get a proper inspection for that, it’s obviously pointless. However, if we’re talking about significantly higher amounts, you have to ask yourself if that is proportionate for a standard single-family house. What do you think?

3300 euros is quite a lot of money for the appraisal. An external independent expert will not (or hardly) cost more, as long as everything goes more or less smoothly.

The expert must of course be independent and must in no way be on the salary/client list of the object manufacturer being inspected. Which expert you choose is entirely up to you and does not have to concern the construction company further. As long as you are working with a general contractor, they can't do much about it either, since it is your property and you can invite whoever you want. It looks different with developers, as there the contractor is the owner of the property with house rights, etc...

This is probably about the intermediate and final acceptance which almost every provider now does with TÜV/Dekra. Or am I mistaken?

your problem is that you simply make stupid claims without any basis. I have already tried to point that out to you, but you perceived it as a threat.