Plaster and sand concrete filigree ceiling Q3

Hello,
we are about to hand over the house and now have a problem. Our painting company on the builder's side was supposed to putty and sand the entire house in Q3 and then apply painting fleece and paint white. Due to delays, we received the information that they are now entering a time window where no capacities are available anymore. We naturally panicked because every painting company laughs at you when you ask for short-term capacities.

So we accepted an offer from the builder that the painters at least putty and sand the house and that we would have to do the renovation ourselves if necessary.
Now we were lucky to still find a company that will wallpaper the house, but as we almost expected, there are problems if two companies do the painting work. This specifically concerns the concrete ceilings on the ground floor.

Company 1 had in the offer to putty and sand the ceilings, 70 sqm in Q3. In the end, only the joints between the panels were worked on, which we would have received in Q2 anyway according to the construction service description. Of course, 70 sqm are to be charged even though maybe 10-15 sqm were worked on. In my opinion, this is quite borderline.

Company 2, who are supposed to wallpaper the ceilings, now say that the ceilings are not in Q3 condition and that the interplay of concrete and putty could shine through the fleece. They will putty the entire surface in Q3.
I already know that if defects occur, one company will blame the other. Of course, that is our fault, but we were forced into this situation by the short-term failure of Company 1.

Are there any guidelines that specify how concrete ceilings are supposed to look in Q3? That is, fully puttied or only joints puttied?

Who is to blame for the delays? You set a deadline and then they usually come quickly because otherwise it becomes more expensive for them. Can't the new company finish spackling in Q3? Deduct from the general contractor (after prior deadline and opportunity for rectification). I would also not accept the calculation of services not rendered.

What they say about the concrete ceilings is, in my experience, not wrong. We received the ceilings with putty applied (only the concrete joints and holes), at Q2 level. We had our painter do rough sanding and priming, then directly wallpapering. So no puttying/sanding at Q3 level. We can confirm that many spots on the ceilings are visible in the evening when the light is on, which are not smooth. It doesn’t bother us that much, but if you really want it neat, Q2 as a base surface is not enough.

We will have to have it corrected again in the coming years, or live with it. But I also don’t know how much sense it would have made to go for Q3/Q4 and perfect walls here already now. I notice, now that we have moved in, that a lot is still happening in the house. The building is only about half a year old. There is still a lot of moisture here, and especially at the edges of the wallpaper you can see that it is partially peeling off. No matter what level you putty to, you can’t putty out the moisture from the raw building. We will not touch the walls/ceilings anymore until at least a year has passed and the house is properly dry and hopefully no longer settling so much.

Company 1 was supposed to include in the offer to fill and sand 70sqm of ceiling up to Q3. In the end, however, only the joints between the panels were treated, which we would have received anyway in Q2 according to the construction service description. Of course, they wanted to charge for 70sqm even though maybe only 10-15sqm were worked on. In my eyes, that's already borderline.

In my opinion, this is not okay, since ultimately only the joints were treated. Depending on how high your standards are or how much it will annoy you, I would definitely make sure it is done the way I want it. Of course, you can see transitions between materials or substrates later if you look closely. Often it is also the case that not only the joints are filled, but large areas are skimmed because the ceiling panels often do not lie exactly millimeter-precise.
If you want it "done right," you should have it fully skimmed, or you live with possibly partly visible spots at a lower price.
Ultimately, it also depends on what will be applied to the ceiling afterward and how this material visually compensates for such deficits (e.g., textured paint); added to that is the type of lighting, the room height, etc.