Young couple (student and engineer) want to build

We are buying everything together from the developer, what I just didn't want to include are 400€ from her side job. If I could just buy the land it would be a clear case, buy and wait....
Purchase of property is considered, for smaller expenses our parents will surely support us but we should still be able to get by. We are not going on vacation anyway....

Complete calculation:
Me 3300 net + her 400€ side job (student)
After the wedding in a month:
3700 net + 400 € side job.
In the internship:
3300 net + 1000-1200€ net

The bank will be the crucial point here. If you find one that does it, basically nothing speaks against it. Here, the future situation is exceptionally more decisive than the current one. If parents also stand behind as a safety net, even better. With a property developer, the cost risk is also manageable. So, make appointments with banks or better yet directly with financing brokers (Interhyp and co.). If decent conditions come out of it, seize the opportunity! The salary is good for the age, and the future prospects of the woman are also absolutely solid.

Why do you have to finance so much with 200 equity and a 550 house price? Because of kitchen upgrades, furniture, or what?

No real estate transfer tax, notary, buffer due to own work and KNX.

Approach your house bank; they know your situation. What bothers me is that the house and financing are in your name, and she gets "zugewinngemeinschaft."

Does that mean your future wife will never be entered in the land register?

If I were in her position, I would refuse. After all, she is helping to pay off the house.

No real estate transfer tax, notary, buffer due to own work and KNX.

What about all the rest then? Small stuff unfortunately really adds up...