Construction financing - what can we afford?

If I were you, I would also have stomach aches, especially since the total costs are not really clear. We also have stomach aches in our case and have now nevertheless dared to go ahead, and our loan amount and income are similar. Our loan is 650,000 and our average income is about 8,000 euros. The difference is that we are already in the situation of having two children and know what that costs us, we are building with a developer and can therefore calculate the costs a bit more precisely. You are, of course, civil servants, which is hardly topped in terms of security, but keep in mind that your wife with children might not want to or be able to work full-time anymore. I think if I were you, I would look for something more affordable.

I was assuming 700K€ for house + land the whole time

At just under 900K€ total costs, I would definitely drop out.

That was correct.
The architect gave 700,000€ for land + incidental acquisition costs, house + ancillary costs, double garage, architect’s fee, photovoltaics, and kitchen. As written, according to the architect we could furnish it for 700,000€. I never mentioned anything about 900,000€.

It is also not 5,500€ net, but at least, if you deduct the child benefit, 6,600€ net.

That was also the right thing to do. The architect stated the 700,000€ for the land + incidental acquisition costs, house + HNK, double garage, architect's fee, photovoltaics, and kitchen. As written, according to the architect, we could furnish the place for 700,000€. I never said anything about 900,000€.

It is also not 5,500€ net, but at least, when you deduct the [Kindergeld], 6,600€ net

Definitely ignore the [Kindergeld]! On the contrary... don’t believe that you can get by with the ridiculous 180 EUR [Kindergeld]. I don’t know anyone who has such a high income and at the same time starts to save on the children! I would find that quite ignorant and "modest"! Our child currently costs us about 1,100 EUR per month. However, this includes private health insurance, private daycare, and 200 EUR for clothes + outings (zoo etc.). The expensive private daycare actually wouldn’t have been necessary... unfortunately, there was no acceptable daycare here with a free spot.

don't believe that you get by with the ridiculous 180 EUR child benefit.

- If it's ridiculous, feel free to transfer me the amount. - It's even a gigantic 190 euros child benefit.

I think saarschwabe is now playing stubborn. Here is a small pro / con list

+
good secure income

-
unclear construction costs that keep rising
special repayment that wants to be paid from fictitious items
very high loan compared to income
hardly any equity
no child, but desire for children associated with risks like disability, part-time work, daycare costs, etc.
huge house with a lousy plot

- If it's ridiculous, feel free to transfer me the amount. - It's even a gigantic 190 euros in child benefits.

Considering what our state spends money on, the child benefits, even in the total sum of all receiving parents, is RIDICULOUS!