Construction costs are currently skyrocketing

When I look at the calculation above... 2,900 EUR/m² with tiles, parquet... alone interior doors for 10k (I budget 3,000 EUR for 10 doors as own work...)

These 2900€ already include the built double garage. As you can see, the equipment is high-end. We just try to get high-quality things as cheaply as possible. The entrance doors alone have an RRP of 15k, We also got the aluminum windows cheaper through acquaintances. Faucets for 3 bathrooms (guest with shower, children with shower, parents shower + bathtub) we looked at in the bathroom showroom and ordered online. All very high quality, from Gessi, Grohe, Steinberg - RRP 7k, we bought them for less than half (including freestanding Gessi bathtub faucet). The same with ceramics. A freestanding Hoesch bathtub in the showroom costs 6k!!! Online - 2k! With a general contractor, you have to take the overpriced things from the bathroom showroom. For example, we also took the kitchen as an exhibition piece. From Leicht with high-end appliances and a Dekton countertop. RRP 38k, we also got it for half. Since we reserved the kitchen very early, we were able to move the walls accordingly. With a general contractor, this would not be possible. etc... So far, we haven't done anything alone. Of course, we have a lot of stress coordinating the trades and the risk that something goes wrong...

... With a general contractor, you have to take the overpriced things from the bathroom showroom out ....

I have a déjà vu there. We were almost kicked out of the store during the sample selection when I said, "We'll take that out from the GC and order it from the sanitary wholesale online." The lady's mood changed instantly :-D

what does “vor sich her schieben” mean?

As of today, they have enough completed orders to keep themselves busy for 1.5 years

With a general contractor, you have to take the overpriced things from the bathroom exhibition.

That is only true to a limited extent and depends on the general contractor. And prices that are "we got cheaper through acquaintances" are only conditionally competitive.

And prices that are "we got cheaper through acquaintances" are only conditionally competitive.

The windows also had to be ordered from the manufacturer, and the installation is not just for a "thank you". I know that I got very good windows that are well installed and that no one ripped me off. The sale of the windows works similarly, as already written in a few threads earlier, to the sale of houses: "Oh, you’re asking about aluminum windows? Then you must have a lot of money... The extra 10k probably doesn’t matter to you anymore..." Through the acquaintance, I learned that large lift-and-slide aluminum windows are sometimes cheaper than those made of PVC. The PVC windows have to be specially reinforced, which drives the price up. If you assume from the start that aluminum is "unaffordable," you miss many alternatives.

….. we were able to move the walls accordingly. With a general contractor, this would not be possible.

I can't just leave it at that. Maybe for one or the other. But the walls I moved, thereby creating more or less a new (larger) utility room, was no problem at all with my general contractor. It didn't even cost extra, which some might not be able to imagine. Another general contractor would have been possible too, but with additional costs.