Not all electrical cables are laid in empty conduits! What to do?

If a conduit installation is part of the contract, in my opinion the conduit must also be installed all the way into the box; otherwise the conduit is useless, as cables cannot be replaced afterward, which is the purpose of a conduit. In the described case, it only protects the cable during embedding in the screed ... Whether conduits are useful or not is up to each individual to decide, but if they are promised, they should also be installed properly.
Best regards
Matze

If the installation of the empty conduit is part of the contract, in my opinion the empty conduit must also be installed all the way into the box, otherwise the empty conduit is useless, since cables cannot be replaced afterward, which is the purpose of an empty conduit. In the described case, it only protects the cable during installation in the screed ... Whether empty conduits are useful or not is up to each individual to decide, but if they are guaranteed, they should also be installed correctly. Regards Matze

True. However, due to the minor nature of the issue, I would not go to the builder with sharpened knives. Destroying the relationship over something like this would be rather harsh, I think.

from practical experience: I personally prefer not to connect a CAT7 network cable without a protective conduit / empty conduit in the outlet. At least a small margin is needed, even if it is only 1-2cm that the empty conduit provides in addition to the hopefully deep flush-mounted box.

Not fun for the electrician and, as already mentioned, neither compliant with standards nor ordered.

This is how it will look in 98% of all solid construction houses. Plaster over it and it's fine. Don't worry.

The saying that comes to mind is: "We've always done it this way" Does that make it better?

It is an indisputable fact that the installation was carried out differently than ordered. Therefore, the OP is entitled to a refund for the saved pipes. In addition, he is entitled to a reduction in value. In this respect, is fully right; it was simply not built according to DIN 18015. This standard indeed requires installation in a conduit. However, this is not to protect Abel, as often discussed here (damage to a plastered-in cable is not to be expected even with very agile children), but to be able to expand or change the system when data technology changes. Therefore, it must be weighed whether to have it changed (you would have the right) or to have the considerable defect compensated.

The saying comes to mind: "That's how we've always done it."

Does that make it better?

Regarding the ordered service? No.
Regarding a functional electrical installation? Yep, it has always worked flawlessly. Problems start at the earliest when the house needs a complete renovation anyway. The average homeowner doesn't experience that.
With regard to data cables? CAT7 is sufficient for at least up to 10 GBit/s. Even here, security is guaranteed for the next 30 years. Not even anyone installs Cat7 sockets.

Therefore, I would be relaxed about the performance of the installation for my lifecycle. However, I want to receive what I order and pay for.