Since I can no longer edit. Has the private health insurance already been deducted at 2986 for your wife? If she is a high school teacher, probably yes, if she is an elementary school teacher, probably not yet.
I would simulate the whole thing with 1-2 children in 3 years! Why? Surely one of you is working part-time. And I don't see the targeted [1.300€] financing here. It will be more plus the ancillary costs for the house. You will certainly end up at about [2000€] / month. You have to want to manage that financially with part-time work.
Since I can no longer edit. Has the PKV already been deducted for your wife with the 2986? If she is a high school teacher, probably yes; if she is an elementary school teacher, probably not yet.
No, not deducted yet. Secondary, middle, comprehensive school
It's a great starting position. Buy the land, pay off the car loans within one year, then you still have 2 years to save equity for the interior design (kitchen etc.) and repay the KfW loan. After that, the 1,300 euro installment, which corresponds to roughly a 400,000 loan, is no problem. In 3 years you'll manage it well. Maybe 2 years will also be enough. By the way, we just built. 168 sqm for 400,000 without garage. Sure, you could definitely save 20,000. Then there are also 100,000 for architect/additional costs/furnishing/kitchen.
I'm also considering that. But I'll recalculate what will actually remain per month for saving if we service a loan for the land.