No construction and performance description in GÜ for freely planned house

Verbraucherzentrale is, in my opinion, also the wrong partner for a construction contract review. Find yourself a construction consultant or a specialist lawyer for construction law.

But if I have a shopping list, I might know that I’m getting a gypsum plaster, but not whether it will be Q2 or Q4.

Whatever. Then he just doesn’t have his own construction company. But he "builds" your house from a single source (with the companies he hires).

Sure. In the best case, a trained office clerk checks, based on a checklist and sample construction and service description, whether all items are included. The item "windows with glazing according to the current Building Energy Act" gets a check mark – even if windows with double glazing and catastrophic sound insulation, manufactured in the hinterland of the Congo, are installed. There is no actual technical inspection or specific attention to quality.
This is assembly line work at the consumer advice center, nothing more and nothing less. Individuality cannot be provided – nor is that even the claim. The service of the consumer advice center is okay for what they do. But not for you.

That is why the LV should be checked by a professional (which in combination is clearly better than a standard construction and service specification from the Verbraucherzentrale). Due to the level of detail, there are ultimately no discussions.

A somewhat reasonable specification of services (even in the tender documents available online as samples) provides for a significantly more detailed level of detail than you will ever get in a "normal" construction and performance description. In the construction and performance description it says "Plaster as gypsum plaster on ceilings and walls in Q3" - that's it. ==> The consumer advice center likes that In the specification of services, in addition to the two aforementioned points, the materials and processing steps are sometimes also included ==> a non-expert may possibly not understand Deswegen the specification of services should be checked by a professional (which in combination is significantly better than a standard construction and performance description at the consumer advice center). Due to the level of detail, there are ultimately no discussions.

If this has the higher level of detail, the question remains why the specialist lawyer for construction law does not want to review the document. Or is the problem with the consumer advice center, which does not understand it and therefore does not forward it? Then the original poster will have to find a specialist lawyer on their own, without intermediary. If that lawyer also does not want to review it, then I would become alert.