Construction costs are currently skyrocketing

With a fixed price, I wouldn't even consider changing anything or not starting. Just don't make any more changes that could cause a price adjustment.

Ok thanks to you. Then close your eyes and push through :)

What kind of irrational thoughts are these?
Construction start is just around the corner, a super long fixed-price guarantee, and yet your knees are going weak. It doesn’t get any safer than this.

I wouldn’t cancel/hand over the current residence too early, but otherwise you can just lean back.

If you shout stop now, you’re sure to have a six-figure loss in your pocket. So pull yourself together.

As far as I know, there has never been an oil price shock without a recession. ... If the house now costs 400k 18 months later instead of 300k – no wonder.

Unfortunately, I did not understand that, could you please explain it to me? I have learned it like this: "... the purchasing power of consumers decreases and prices fall. Classic features of a recession are: decline in demand, overstocked warehouses." But that would mean that houses should rather become cheaper than more expensive? Thank you for your patience.

Both directions are currently possible. Increasing prices due to a higher share of energy costs, or decreasing prices due to lower demand. It is possible that building materials become more expensive and construction services tend to be cheaper. And then inflation is also generally running out of control right now.

Another demand effect for housing will come from the renewed wave of refugees. The construction industry and prices can really go in any direction at the moment.

Yes, we have nothing paid in advance, everything is only paid after (h)completion. And we also have an external construction supervisor who checks all relevant progress. Still, one starts to doubt by now.

In the end, it still doesn't help if more than 60% goes to the shell construction. It already starts with "site setup". They put a porta-potty there and want 5-10% of the final amount :D