Remove prefabricated house walls and ceiling panels for electrical installation

That sounds to me like the naive idea of trying to translate the process of chiseling slots into the logic of wooden house construction. The paneling of a structural ceiling is also poorly comparable with the insertion panels of a decorative suspended ceiling. Moreover, the question arises for me (and probably also for some other readers) as to why one does not simply order a shell stage in such cases. "Incomplete plus" is always easier to realize than "Complete minus and back."

The answer is quite simple - firstly, of course, to save some money but even more importantly, to get it the way I want it - which the house builder either cannot deliver or would only do so at an exorbitant price. And of course, simply because I can. Both the wiring and the connection of various smart home devices are no problem for me - but I do not see why I should pay the house builder a five-figure sum for this simple task when it seems possible to do it otherwise.

Your plan is at least unusual. That raises questions: Do you already have a plan where which cables are supposed to go for what? Do you want / need to protect this wiring separately? How much space will you have in the fuse box? How will you get there? What effect will your intervention in the electrical system have on the warranty of the entire electrical installation?

- Pretty much, yes - reality will show whether a few slats/beams are in the way in detail
- 24V - fuse of the power supply is sufficient
- Enough
- I will have the house builder lay a cable to every room and then distribute it myself
- None at all, as I am electrically skilled enough

- I have the builder lay a cable into every room and then distribute it myself

Your answers are clear and with a cable already laid in the room you can work well. With ultra-flat cables you will have less effort hiding them. If you want to remove and reattach "panels," they should be suitable for that. I don’t recommend this for drywall or Fermacell.
Besides laying the usual NYM cables in walls and ceilings, there is the alternative of open installation as a feature, for example with cables from GI Gambarelli.
The "Kasten-Bier" suggestion actually seems cheapest to me. If you are there on the day of installation, you can possibly have the cables laid right to the desired spots or even lay them yourself as long as everything is open. A small mark at the spot and you retrieve the cables after acceptance through a deliberately made hole.

Your endeavor is at least unusual.

The special request is as common as it is not to be considered in the planning of the previous job order, we live in an era of non-indicators.

That raises questions: Do you already have a plan where which cables are supposed to go for what? Do you want / have to secure this wiring separately? How much space will you have in the fuse box? How do you get there? What effect will your intervention in the electrical system have on the warranty of the entire electrical installation?

At least "interfaces" for the "on-site" installation expansion should be included in the general contractor’s planning, and of course, even if these rarely require their own fuse circuits, they should at least be considered in the loads to be secured. Ideally, there should also be an interface / "network termination" between the warranty areas of the general contractor and the customer electrician.

- Pretty much, yes – reality will then show whether a few slats/beams are in the way in detail - 24V – securing the power supply is sufficient - Enough - I have the house builder lay a cable to every room and then distribute it myself - None at all, as I am electrically skilled enough

Pretty much is a weak answer (not to us, but the builder himself should have a more precise one). Where exactly do the 24V connect to the 220V~? (Also) in warranty matters, some things must be done not only by experts, but also by those authorized to do so.

I do not see why I should pay the house builder a five-figure amount for this simple task when it seems possible otherwise.

Well, as long as, even after offsetting the additional coordination and demarcation efforts, there remains a solid four-figure difference (and you are only a connoisseur in a few or even just one trade and have specification-compliant claims in all other construction services).