Cancel the loan and accept a better offer?

How did you solve that in your family planning?! Did you take that into account? If so, how?

This is about the following consideration: right now we are still young and can repay a lot. But in 2-3 years we want to have children. Then one salary will initially be lost. For this period, I believe 300€ is simply 300€. With one salary gone, 50% of the income disappears. Okay, there is still child benefit and childcare allowance. But I assume we will have losses of 1400€. And 300€ is already a significant amount.

We don't have children yet, but everyone tells us: children cost a lot of money ;) And for this period, we would just like to have a solution.

I assume that we will neither pay off the loan in 20 years (end of the fixed interest period, so about 90k remaining)
nor do I assume that we will need 30 years. I think we will end up somewhere around 25 years, with special repayments.
The charm is that with the 30-year loan we could also repay the KFW loan after 5 years, and then have an additional 170€ available. After another 5 years, another 170€ could be available. That means after 10 years we would face a minimal rate of 1522€. That's the advantage of the 30-year solution. Here we would combine 2 KFW loans.

The alternative now is:

20 years 150,000€ at 1.78% and 20 years 300,000€ at 2.04% - in mix this also results in 1.89.
Advantage: With a lot of goodwill, we could have already paid off the 150k in 10 or 12 years and would then have a roughly 700€ more relaxed rate, so it would be similar to the 30-year loan. But only after 10 years.

But we want to have children in the next 2-3 years. Hence the consideration.

How did you solve this in your family planning?! Did you take this into account? If yes, how?

Our house construction project started before the birth. Construction then began shortly after the birth. I definitely do not recommend it.