Financing Strategy House Purchase Interest-Free Period

If payment is made, the loan is drawn on and interest and repayment are always due. Everything else is wishful thinking.

That is not entirely correct. If I agree with the bank on repayment-free months/years, then for the agreed period only the interest is due and not the repayment.

We do not actually know the specific situation of the OP and can only pass on personal/professional experiences here.

For the buyer, such a situation is of course absolutely undesirable. This would lead to a double burden.
But is there really no freedom of contract to agree on when the price is paid?

You are right, there is freedom of contract and I can design whatever I want as long as it is not immoral.
I have the feeling here that two things are being mixed. On the one hand, this is the contract design with the lender. It is possible that he grants a repayment-free period, but he is not obliged to. And the second is the contract design with the seller. However, he will generally want the purchase price upon transfer of possession. If I remember the law correctly here, you bought a house and renovated or remodeled it before moving in. That is the identical case. I don’t think that the seller initially did not want any money.

I would also advise every seller against handing over the keys for renovation before the purchase price has been paid. I had such a case professionally where the buyers noticed during the renovation that their calculation was off and they refused to pay because the house was supposedly so bad. The sellers then had to take legal action to recover their money.

I would also advise every seller against handing over the keys for renovation before the purchase price has been paid. I had such a case professionally, where the buyers noticed during the renovation that their calculation was off and they refused to pay because the house was supposedly so bad. The sellers then had to recover their money through legal action.

Correct. And either you have the money for such a project or you don't.

However, he will usually want the purchase price at the time of transfer of possession. If I remember the law correctly here, you bought a house and renovated or rebuilt it before moving in. That is the exact same case. I do not think the seller initially did not want any money.

Of course, I paid after the purchase, completely correct. The handover took place two weeks later.
Here it is different: the handover is supposed to be in November, which is still a long way off. The purchase contract will certainly come into effect much earlier. And when the purchase price is paid, the parties can agree on that. After signing, at the latest at handover. And if payment is to be made promptly, at least interest will be incurred. Even though the buyer does not yet have possession of the house.

we mean the same thing, talking past each other. Of course, you can make the contract now, but paying upfront is nonsense. Contract now and pay upon delivery.