LAN cabling in single-family house (prefabricated house)

Hello to builders and possibly also to electrical specialists (men/women),

since I have not found anything about this on the internet or forums, I am asking the question here again.
We awarded the interior work through the BT, unfortunately also the electrical planning. Of course, LAN cabling is not included in the standard, which the electrician charges extra for. Is the position cable (CAT7) plus pulling cables in the house (floor area 130 sqm) for 300 gross (only one LAN cable, double price for two) too expensive or reasonable? Laying the data cables and network sockets are extra.

We are getting a prefabricated house (wood frame) with a ground floor and upper floor (=roof). It is planned to have the telephone node in the utility room, to install a router and switch there, and to serve the rooms from there each with a double socket and double line Cat7.
The electrician charges a lot for this and also, which really confused me, he wants to install the LAN cables in an empty conduit (allegedly for protection). However, despite the empty conduits, cables could then no longer be replaced! Does that make sense? Is there a DIN for this or is it standard practice not to install the cables openly? Who has experience here or has done this before? As I said, so far we only have the laying service with placing the cables on the socket. The rest in the utility room is not included yet!

Could this service possibly also be done by an amateur? The ceilings are still open, the lines will be laid on the rafters, and in the horizontal there are installation lines or the walls are not insulated everywhere, so cables can be pulled there.

Thanks in advance for professional feedback.

Regards, Charly

State of the art is to lay network and coax cables in empty conduits. The reason is that these types of cables must not/should not be deformed. Typically, the empty conduits should also be laid in such a way that the cables can be pulled. In other words, no mess at the bending radii of the installation.

That is not the reason... you can bend the cables however you want, as long as you follow the installation guidelines of the manufacturer... the reason is this... as described in DIN 18015... data cables can be routed interchangeably.

However, despite the conduits, one could no longer replace cables! Does that make sense?

Yes, the conduit, but not the statement

For double boxes, I would also install double cables, structured cabling is installed "fully," Cat7 and Gigabit also suggest this; cable sharing is actually not done "planned."

Pulling in two cables either takes no more effort at all (because you pull them together) or infinitely more (if the conduits are only small tubes). That is helper work. Installing the cables onto the sockets and the patch panel is more a job for the professional.

That is all Hiwi work. Still, 300€ is not the end of the world, probably depends on the cable lengths and number of sockets. Work is not free either.

Um, 300€ for all the cables together, right? At first, I understood it as if that were the price per cable. That would of course be complete rip-off. For all of them, on the other hand, it's quite cheap if slot chiseling, installing sockets, etc. is included.