Construction costs are currently skyrocketing

The other way around would mean that you do the work for the house just as quickly and well as the professional, which is rather rare. If you now take 50% longer, you can apply 150% of the professional's hourly wage. That should fit well...

Unfortunately, this will not fit for many craftsmen these days either. With an already good hourly wage (at least here in the region) of net 20 or 25 euros, the tiler should cost 30 to 37.50 euros. You won't get one for that. If you even get one at all. And if they then work well.

The other way around would mean that you do the work you put into the house just as quickly and well as the professional, which is rather rare. If you now take 50% longer, you can spend 150% of your hourly wage for the professional. That should fit well...

A rule of thumb for Germany is a factor of 1 to 5: So to commission 1 hour of your own work (gross price without material), as an employee you have to pay about 5 hours net.

The "remaining" 80% of the paid wage is shared between employers, the state, social security funds, landlords, lessors and the Chamber of Commerce.

Elsewhere in neighboring countries it is rather 1 to 3. Among other reasons, formalistically we may be a "rich country," but not as much of it reaches one as in other "rich countries." At least as an employee. For employers, the state, social security funds, landlords, lessors and the Chamber of Commerce it may look different :p:D

The other way around would mean that you do the work for the house just as quickly and well as the skilled worker, which is rather rare. If you now take 50% longer, you can invest 150% of your skilled worker’s hourly wage. That should fit well...

However, 'skilled workers' in construction are really a rarity. In practice, the subcontractor comes from the subcontractor.
And even if a German craftsman gets hands-on himself, he first has to go to the hardware store, then take an extended break, and then he has to attend an emergency at another construction site.
In my opinion, doing it yourself also has the advantage that you can do it properly.

'Skilled workers' in construction are actually a real rarity. In practice, the subsub comes from the sub.
And even if a German craftsman pitches in himself, he first has to go to the hardware store, then take a long break, and then he has to respond to an emergency on another construction site.
In my opinion, doing it yourself also has the advantage that you can do it properly.

I cannot confirm that. At least not with the trades our general contractor works with. All very friendly and happy to advise when I ask. The quality of the work is also very good.

I cannot confirm that. At least not with the trades that our main contractor works with. All very friendly and happy to advise upon my request. The quality of the work is also very good.

You also had an extensive search for the best main contractor in Berlin/Brandenburg, did everything right

I completely agree with you. With an older house, you are usually comforted about the compromises by pretty details (or "nostalgic charm"), whereas with a new build, in my opinion, there is nothing like that. Our last house from the 50s had details that we and many others cannot afford in a new build and that we miss.

What details do you mean? The advantage of old houses that I see is that practically all of them here in the south have basements. I don't really find any arbitrary projections and recesses in the building shape charming ;)