Home financing - please provide an assessment

Counting on income that you do not yet have, but potentially could have, is always dangerous.

PS:
Also think about the children. I don’t think it’s fair if they have to do without everything for 10, 15 years because you overextended yourself with the mortgage. As I said, go to the discount stores sometime. A house can also be built for 2,500 or 2,200 EUR/m².

But I did say... I certainly trust 2 30-year-olds and especially an engineer to put in a lot of their own effort.

I would rather mow the lawn or plant the hedge myself, so the kids can watch or help... instead of working overtime for 25 EUR/net per hour, only to have the gardener come for 60, 70 EUR/gross per hour.

We are currently operating with about €5000 net (including €500 child benefits) and saving €1500-2000 per month. I don't see any problem planning like the OP for the next few years. And to argue that the children have to do without everything for 15 years I actually find wrong here. Because especially the fixed costs for the house remain constant, while the salary keeps increasing. Especially at the beginning as an engineer. In an emergency, the company will be changed, then you get a 15% raise.

Nevertheless, personal contribution of work also helps enormously.

I think it is quite naive in the current economic situation, especially in the industry, to expect constantly rising salaries. But fortunately, that is just my opinion, no one has to follow it.

A vacation in Rhodes for 4 people during the autumn holidays costs around 3,000 to 3,500 EUR. Just to get a feeling... of course, you don't need all that. You can also sit on the terrace and sip ice water.
But you have to be aware that such vacations are off the table for 10, 15 years if you spend 40, 50, 60% of your net income on the loan and the additional costs of the house.

As I said. You should plan with what you have. No one can predict what tomorrow will bring in the current situation...

I think it is quite naive in the current economic situation, especially in the industry, to expect constantly rising salaries.

A company that fails to give a young engineer a raise every year, in my opinion, deserves to go bankrupt. I do not know the OP's environment and the OP also did not write what they do. But as long as there is not only one potential employer there, I still see few problems.

A vacation in Rhodes for 4 people during the autumn holidays costs around 3,000-3,500 EUR.

Then I simply don’t go to Rhodes during the autumn holidays, but a few kilometers north to Albania and get all-inclusive including rental car and an apartment on the beach for even less than 1,000€. Almost everything is possible – after all, you are also the one who preaches that building cheaply is possible. Why can’t living cheaply without real restrictions also be possible? I don’t understand that.