Construction Financing - Fixed Interest Period

The KfW components with the same interest rate have no added value - best to finance without them and thus remain more flexible.

I see it the same way.
But maybe he only gets the interest rate for non-KfW through the KfW components?!
The "problem" with KfW is usually the repayment, because it is fixed.
How high would the repayment be in each of the 3 loans in this case?

I would have other combinations offered.
What would interest and possible repayment look like for 15/20 years?

But maybe he only gets the interest for non-KfW through the KfW components?!

For us, it was independent. In my opinion, KfW is only worthwhile if it is lower than the regular interest rate and thus results in a lower mixed interest rate. A KfW loan is optional, not mandatory.

First, I would hire several financial advisors. They actually provide different offers (experienced firsthand). However, what you are then promised can be something else. The proposals from the financial advisors do not have to match the offers from the banks. Otherwise, approach regional banks yourself and ask personally.

0.95% does not sound particularly good with 20% equity and a 10-year fixed interest rate. Interest rates are currently falling. In my case, I got 0.96% for 10 years now, but we already have a bank registered in the land register due to the property financing. If that were not the case, we would probably have gotten a slightly better interest rate.

I think if I get the contract award, I will still get an offer from my house bank, fully aware that they are usually not the cheapest. But they already have my data from another offer. How is it actually with the Schufa? If the financing broker obtains the offer from the bank, that affects the Schufa, right? That means if I get, say, 3 offers now — 2 from a broker and 1 from the house bank — then that would be 3 Schufa inquiries. Is that problematic?

I think that if I get the contract award, I will have my house bank make me an offer as well, fully aware that they are usually not the cheapest. But they already have my data from another offer. How does it actually work with Schufa? If the financing broker obtains the offer from the bank, does that affect the Schufa? That means if I now get, say, 3 offers, 2 from a broker and 1 from the house bank, then that would be 3 Schufa inquiries. Is that problematic?

The financial advisors/house banks only ask Schufa when it becomes concrete. For the first inquiry, Schufa is not contacted at all.

Best to simply calculate (or have calculated) all scenarios.

There are financial advisors who can do this off the top of their heads.

But for you as a start:

Calculate loans with 10 years. Assume the remaining debt, then simulate if interest rates stay the same, fall, rise—it's best for us to do this with several interest rates.

Depending on how much extra repayment you can make, you will get very different answers.

Important: never take risks just for a few thousand euros in interest savings. Also, don't forget inflation.
My current tendency is to choose a longer fixed interest period and play it safe.

But as I said: calculate (or have calculated) everything and then weigh risks thoroughly.