Necessary insurances for new construction

In terms of priority, I would say: (1) residential building insurance or fire shell insurance (2) builder's liability insurance (3) construction all-risk insurance

We had builder's liability insurance and construction all-risk insurance during the construction.
From completion onwards, residential building insurance (see below).

- "Top-Schutz" tariff from the provider "Domcura"

I have this tariff with this insurance and have already had a claim. The settlement proceeded absolutely without complaint.

I have already answered that. One can discuss the coverage levels and insured claims. However, not the "whether" at all. All insurances are reasonable (depending on the financing amount, they are obligatorily required by banks, so you don't even need to think about it anymore).

And I had only asked about the "whether" regarding the construction performance insurance as well as the elemental insurance. :-)
In the financing offer available so far, only fire insurance is required, or subsequently the residential building insurance. These are unquestioned. Otherwise, no further insurances are demanded.

I was just surprised by what those prices are. Back then, I got a package directly from the house construction company that covered everything. I think the residential building insurance had a duration of 1 or 2 years after moving in. I canceled and took out a cheaper one. That’s about follow-up costs. I think I paid around 250€ each year back then. When I run a comparison via Check24, the numbers with your stated services aren’t that far off. I could only try it out with my postal code now.

For your palace, 750 EUR/year for a residential building insurance is not much, is it?