Construction costs are currently skyrocketing

Yes and no, the DIN4701 was valid until 2003, after which it became invalid. Simplified procedures are still based on it.
Since then, the heating load has been correctly calculated according to DIN EN 12831.
You probably just found some very old performance specifications.

The hydraulic balancing is not legally required. However, it is a prerequisite for funding.
Apart from that, a heating system without hydraulic balancing doesn't make sense. For safety, the hydraulic balancing should be explicitly included - because, as always, you only get what has been agreed upon in writing.

Hydraulic balancing should actually be unnecessary in new buildings.
Give the heating engineer the energy calculation of your house.
He can then determine the hydraulic balancing for each room based on the room heat demand, the pipe length, and the calculated pipe friction losses.
Then the actuators hardly remain necessary, and the heat pump operates at maximum efficiency.

In my case, the engineering office of the heat pump manufacturer calculated these values for the heating engineer. That should actually be possible with a heat pump costing 7-10k.

Dentists, tax advisors, TOP executives, heirs, etc. - there are already enough, no worries. You just end up among your own kind ;)

Dentists, tax consultants, top executives, heirs, etc. – there are already enough, don’t worry. You just stick to your own kind ;)

Isn't it already like that. Perfect surroundings for plastic surgeons and lawyers. :D

1.2 million at 2.5% interest and 2.5% repayment are 5 bills per month

Rather 25 bills. The thousand-euro bills have never existed with the euro anyway, and at least the 500-euro bills are officially considered quite dubious in relation to terrorism..;)

If the price in 08/2023 is too high, he can terminate the contract without costs, right? Otherwise, the main supplier could demand exorbitant prices without the builder being able to defend themselves.

Normally, GCs are also tied to price indices and cannot just call up any amount they want. Also, what else should one do in August 2023? It won't be cheaper to start the planning all over again in more than a year.

We still got a 13-month fixed price guarantee from our GC (signed the offer last week). They currently also have a 15-month delivery time, but the fixed price guarantee is extended if the GC is responsible for the delay. We just have to make sure to get the base slab done on time.

No normal prospective builder with a €4000 family income comes here anymore and wonders if their project could be viable.

This is partly because everything here is talked down anyway. If someone has an average income/budget, they are told the planned project is impossible anyway. If the income fits and there is enough equity, they are told that material prices are exploding and soon nothing will be available anymore. If a lot of equity is available, people start questioning where all the money comes from. With so much pessimism and envy, you think twice about whether you should really create a thread.

That is partly because everything is always talked down here anyway. If someone has an average income/budget, they are told that the planned project is impossible anyway. If the income fits and there is enough equity, they are told that material prices are exploding and soon nothing will be available anymore. If there is a lot of equity, it is immediately questioned where all the money comes from. With so much pessimism and envy, one thinks twice about whether to really create a thread.

But it was no different in all the previous years. And there was always the positively thinking faction as well. Nevertheless, there are currently significantly fewer people willing to build who are now starting fresh (after the cold KfW withdrawal). That can be explained quite quickly by the general conditions.

But, to provide an exception to the rule, a new thread did appear today. ;)