BV single-family house with full basement

I would keep my hands off it and honestly advise you against it. Better do the door-to-door canvassing and other desperate acts yourself to find a plot of land separate from the provider. Or sign a proper developer contract right away, where you know the land beforehand.

Do you know satisfied previous customers of this provider? And really those you know personally or found by asking around, not those given to you by the provider?

What I liked best during our search were the developers who named reference projects but said, "please please don’t ring the bell there, we send so many people over that the residents are incredibly annoyed." I then once spoke to a former customer when he was in the garden; he was very talkative about how the construction went. And afterwards, I certainly did not want to build with that company anymore.

Asked the other way around... what is the point of a contract for the provider if you can cancel it at any time without restrictions and without damage (money)? What kind of commitment does the provider expect from it?

I suspected it... We are not in a wish-fulfillment situation. If you sign this path, then it is that way.

That would make me completely depressed, working full-time in a dark basement - unless a large sloped wall with a window front is planned. I would rather move the guest room to the basement (well, effectively sooner or later you will end up converting the above-ground guest room into a home office anyway)

Yep, I wonder about that too. First of all, the contract would have to be available. But asked another way: what damage would the provider have if I cancel? Exactly, none. Nothing more than a pending transaction.

Thank you for your direct statement. If you could briefly support this argumentatively – possibly under the premise that there is an unconditional right of withdrawal – I would be even more grateful to you.