Fixed interest rate for the entire term or only 10 years?

Phew, you’re losing a bit of the motivation to help you. You seem very convinced of yourself, although you apparently are not deeply involved in the matter.
Simply put, a budget was allocated for the child benefit. I called that a pot. I would have to look up the exact amount again. Nearly 10 billion €. If that’s gone, it would have to be reapproved... do you really believe that will happen again?

I cannot contribute anything regarding the conditions themselves due to lack of knowledge. But I can regarding the fixed interest period. Basically, it depends on your personal situation, your willingness to take risks, and your fundamental need for security.

Personally, I have an extremely secure job, am also well privately insured in case of possible disability, and have only financed 200k. In addition, I do not expect interest rates to rise again to 3-4% in the foreseeable future. The logical consequence for me was a repayment of 3% with a good interest rate in 2017 and a rate comparable to the rent of a 4-room apartment. This allows us to live comfortably, and in a few years the cards will be reshuffled.

However, if I were a sole earner, calculated tightly in a job that does not promise salary increases, with a high rate, then I would have chosen the longest possible fixed interest period. Solely so as not to have to be afraid. The bank charges for this security.

So please assess your personal situation and decide for yourself.

You pay €932 initial repayment per month, if I interpret correctly, and that over a term of 20 years? Even without compound interest effect, I come to €223,680 that is repaid. How can the remaining debt then be only €110k less than the initial amount?

And in variant 1, the repayment suspension loan... €250k for 0.6%, I come to €125 per month... so why are you paying €625? Is something already being saved there?

Generally speaking... repayment suspension, or also saving in a building savings contract, initially cause "losses," because in case one you don't repay, in case two you save but practically earn no interest. At the same time, you pay interest on the full loan amount. Therefore, such variants are always initially more expensive than a classic annuity loan where repayment starts from the beginning. The "consideration" is the security. You know how it continues after the fixed interest period ends. It is your very personal risk tolerance that decides whether this security is worth the extra cost for you.

Generally, why are such complicated constructions offered to you? I wouldn’t get involved with that. "Plain" annuity loan, combined with KfW, possibly (two?) components with different terms (10/20 years), plus an option for early repayment – you can use that if you can afford a higher rate later. That’s it.

I am now throwing a completely normal full repayment loan over 30 years into the room. Current interest rate between 1.50% and 1.55% (I will calculate with 1.55%) and thus €122k interest = costs in 30 years. That immediately rules out the building savings contract = your variant 2 at the beginning. As often, the building savings contract is more expensive...

Who offers something like that? Allianz demands 1.8% for 30 years fixed interest with 20% equity