Ongoing additional costs - Realistic?

The topic is definitely not new. You can google it.

I did and found nothing? Only things like that apparently it is harder to get car insurance with a negative Schufa. Our Schufa would have had to have negative entries long ago, but it doesn't?

We have also switched back to former insurers more than once. Especially now, we have returned to Domcura with the residential building, zero problems.