Fine staking is wrong, who is to blame?

I would deduct the 200 EUR from the invoice for the foundation slab builder after all. Let him sue for it. Provided you don’t want anything else from him. (Abwasser, Außenanlagen, Garage oder so)

I would deduct the 200 EUR from the invoice from the slab builder after all.

Nah, that only costs time and nerves that the builder will surely need for solving other problems.

Let him sue for it then.

He will do that anyway, since he delivered his service according to contract (provided that he actually did, but that has nothing to do with the renewed fine staking). The whole thing just went badly. A builder who is not building his third house cannot overlook such details. Acquittal.

Requested was "[...] floor plan and the open space plan with the registered construction project

So the surveyor does not have the dimensions of the slab at all and therefore cannot stake it out, which is also not standard, so he does not ask. Acquittal.

According to the slab builder, that is wrong

Correct. From his point of view. He is a slab builder. What does he care about the finished house? He builds the slab. Of course the slab dimensions are staked out, so he does not ask. Acquittal. The best thing would be if the foreman and the surveyor meet at the construction site. While the surveyor positions his total station, the foreman drives in the batter boards. Then they look at the plans together and agree on the dimensions. Then the nails are driven in and everything is documented in the fine staking sketch. Would be, would be, bicycle chain... tuition fee.

Yes, it may be that I am simply fed up with craftsmen who indulge their incompetence and/or laziness at the expense of the lay builder, who of course initially naively accepts everything the first person tells him and thus gets caught in the crossfire.

Whoever willingly puts themselves in danger will perish in it. In this case, it was the client who was too stingy to hire someone other than himself as the site manager. The incompetence therefore lies with no one else but himself. Nevertheless, I can understand your motivation for the text since in reality it is often the case. And no one likes to spend the client's money (waste it) as much as unskilled craftsmen.

Thanks to everyone for your contributions, you summarized it nicely. Then I will take over the 200€ and "write it off".

In this case, the client was too stingy to hire someone else as the site manager besides himself.

Actually, we basically have a professional for every role
* overall site manager
* architect
* site manager from the prefab house builder
* sworn building expert (for construction supervision)

Would the coordination surveyor<>foundation builder have been the responsibility of the overall site manager and I did his work? Or did I misunderstand you?

No. The surveyor delivered the fine staking according to surveyor standards (house dimensions).
However, the floor slab is supposed to be narrower according to the execution plans. And the floor slab builder cannot form his floor slab based on the correctly established house dimensions. For me, that is simply a poor performance.
And even the shell builder of my general contractor managed to do that, whom I consider to be rather an below-average shell builder...

If he can’t do that, then yes, it’s poor. If he knows! But why even have a survey if in the end he still has to calculate mentally?! What nonsense!?
I also don’t say please measure 12.38m for me, even though the floor slab is only 12.14m?! ....

And this little issue shows me again that as a client you are often the best construction manager. Because obviously no one you commissioned felt responsible for it. So you have to coordinate again who is actually responsible for the coordination and control of the trades, documents, etc. ....

We are already tired that our counterparts often choose the easy way and/or don’t think ahead. But it is OUR house and our project, and as long as the executed work is of good quality, we take over the management and the thinking and are still grateful for good work, because exactly that part we cannot take over ourselves, the thinking we can. After all, it is our house and no one else is as deeply involved in the details as we are.