New construction - now or wait? Experiences?

I would think carefully about this attitude. Every house purchase costs money, a lot of money, real estate transfer tax, notary, land register, possibly broker, moving.

When I (back then single without a child) moved into my first own property, I didn’t have this thought. In retrospect, that is good 20 years later, I would do it exactly the same way again and that, even though all these arguments were also brought against me at times.

There is no right or wrong in this regard.

I have not sold a single property at a loss. On the contrary, I ended up with a plus on all of them. But that’s not what it’s about.

Claims change, life circumstances change, income changes, why should the house not change then?

I love my home, it is my place to arrive! But I am no servant to the house and if it no longer fits us, then I would consider something else.

Edit: all my former places of residence are also within a radius of about 3 km from my current one.

you have to change yourself.

I correct: You don't have to. But stagnation, both mental and standing still, has never helped anyone.

The OP's children are not even born yet, and users are already advising inheritance.

You save or own (land, companies, houses) to possibly liquidate it when you need it, e.g. in old age, when necessary. That is called wealth. What you have, you don't need to rent.
You inherit when you have something extra and want to give it – the house does not belong to that at first, because it is not extra and has to cover illness and hard times.
Not least, you eventually let your children go and live their own lives and do not necessarily hold on to them.
That is passion: You should also let go or allow separations.

Our daughter now has a medium-sized company, bought her own used house, and has completely different thoughts than having to inherit our little house. My parents still live in their house at the age of 80, their retirement provision, and "inheritance" does not fit at all into the lifestyle of any of us right now. We will probably set an example for others as well.
(For me, third property, condominium, townhouse, single-family house)

We have all left passion, sweat, and calluses in every apartment or house. But that does not mean clinging when fate demands otherwise.
And our houses are simply not castles and palaces.

A few news and "learnings": I found out that a friend knows the neighbor of the property. She then asked him about the property: The soil is apparently very peat-rich (peat was also extracted nearby in the past). I now suspect that this is why the price per square meter is low. Probably there will be additional costs for the foundation on top. Possibly pile foundation. And one more thing: we also inquired with another provider regarding an offer. But here the property would be missing, either "property service" or find it ourselves. When I asked about real estate transfer tax, he told us exactly the same as the lady: total nonsense, he has never heard of it and it has never been a problem. The tax office has zero chance. There is no tied deal here. He cannot believe that there are court rulings on this. I really wonder how competent these prefab house salespeople are.

He cannot believe that there are court settlements on this.
I really wonder how competent these salespeople of prefabricated houses are.

Of course he knows that and is very well aware of it himself.
But he will never see you again after the contract is signed and the construction phase. Therefore, the competence rather lies in the absence of conscience and decency.

I really wonder how competent these prefabricated house salespeople are.

Very competent from the companies' point of view, by pretending to be clueless. However, they will still not bet their hands on absolute statements. And they most likely also know that the building ground contains peat.

How do you actually assess peat-containing or sandy soil? What I have read so far is that these are unpredictable soil structures that require special planning. If we come across something like this again, a soil survey is probably always decisive?