Purchase opportunity for a "too small" single-family house at a "too high" price 120 sqm / 550K

Not that important! The garden is great. We also wouldn't want to buy a property everywhere. Suburban areas or "villages" are out of the question for us. In general, I want to lay a foundation, to provide children and possibly grandchildren with a comfortable situation later :) That's what drives me

Then, I think you should buy the house. There is a lot you can do with it, maybe gradually. And if plots in that location are in high demand or if it is a good, safe area, you probably won't get too many opportunities or, if you do, then at prices that might exceed your possibilities. Based on my experience so far, since it is a prefabricated house and the first groundbreaking hasn't even happened yet, I would always prefer an existing house. Maybe you want to research on the internet for some photos/descriptions of exceptionally well-renovated older houses. If you have good nerves and a stable relationship, I vote for buying it. :)

Generally, I want to lay a foundation, so to put children and possibly grandchildren later in a comfortable position :) That drives me

Then give your children the best possible education or even two as well as the opportunity to make mistakes. If there is still something left, invest in an ETF fund. The children will benefit more from that. My house construction is the exceedingly selfish wish of (especially) my wife and me. The child will certainly enjoy being able to romp around in the garden as well. In the end, though, that only amounts to 10 years. He would probably prefer living in a 70 sqm place next to his best friend. And later, when we look at the radishes from below (oh, I still have to make a will that I want to be cremated), Junior would definitely prefer to inherit 500,000 EUR in cash rather than a house whose residual value in 40 years is completely uncertain (demographics).

What still unfortunately lingers is the fact that we may not be able to stay in our current apartment forever. It is a fact. So we take precautions (or at least try to). Also, our apartment is not quite ideal for 2 school children and older.

I would reluctantly want to be forced to move to the countryside or to a new housing estate someday because there are no alternatives left.