Financing realistically with current interest rate developments

In terms of the sums, it’s tight but probably doable with a lot of goodwill. Although without any big leaps. You always need 2k to live with 2 children, so not much will be left over.

I find it difficult that you’re already counting on the future second salary, even though you don’t live this lifestyle with 2 children yet. I have seen several times that a second child can seriously disrupt families in terms of stress. Whether work will be possible as firmly calculated by you remains to be seen.

Hello,

this is also possible here, however, in addition to the installment, energy costs and other ancillary housing costs are also added. That easily amounts to 2500-2800 per month. This is without special repayment. You may like it, you don't have to.

It's doable, with the 5k there is still room for improvement after the parental allowance. Of course, it's not super comfortable, but it never is.

I consider this to be safely feasible.
Your great advantage is the very high equity and the buffer you keep:

[*]How much equity do you have? 250k €
[*]How much equity do you want to invest in the house project? 175k €

The question is always what the 75k is kept in reserve for? A buffer for the construction is always great, but you could also invest more there. Or you could use the money after parental leave, if it becomes very difficult job-wise with two children. Then you use the money until the second (last) child is in school and you have more time for work again. Even as a sole earner, you should still be able to manage the 2000€ installment. It won’t be fun, but it is doable.
Maybe set the repayment below 2% after all, and prepay any money left over after the house construction? You would have to reliably earn 3.5% somewhere else first anyway.

Well... what interest advantage do you have if you contribute 225k instead of 175k? Especially when the net income for such a project is not exactly overflowing, it is better to keep a little more as a reserve. Otherwise, an unforeseen turn can quickly lead to problems.

I think, of course, 400,000 EUR just for the turnkey house is way too expensive. Can something still be saved there? 50,000 EUR financed at 3,x%, that means a lot of interest at the end of the day.

Does it have to be the double garage right away, the photovoltaic system from the general contractor, the terrace, the conservatory, etc.?

No offense... but 5,000 net and almost 2,000 EUR installment... these questions should be asked.

Well... what interest advantage do you have if you contribute 225k instead of 175k? Especially when the net income for such a project is not exactly abundant, you should rather keep a little more as a reserve. Otherwise, an unforeseen turn can quickly lead to problems. I think, of course, 400,000 EUR just for the turnkey house is way too expensive. Can something still be saved there? 50,000 EUR financed at 3,x% means a lot of interest at the end of the day. Does it have to be the double garage, the photovoltaic system from the general contractor, the terrace, the conservatory, etc.? No offense... but 5,000 net and nearly 2,000 EUR installment... you should ask these questions.

The photovoltaic system from the general contractor is rarely worthwhile. You should compare. There is probably a few thousand euros savings potential there.