Construction costs and financing for apartment or house

I have seen oak floorboards for 30-40€/sqm. How much does installation cost?

Are you talking about solid floorboards? You can easily add another 100€/sqm for that.

Yes, I have seen 20mm solid planks for that price. Do you mean the 100€/sqm for installation or the material price?

Such linings are junk... quite simply. Quality has its price...

Why? And alternative?

I mean today's and future wireless standards, but with smart homes I simply assumed the low-voltage wiring to the switches ... I guess I need to expand my knowledge

Wireless standards in networks = WLAN = a step backward in terms of stability, security, and above all speed.

Additionally, more exposure to radio waves - I would think carefully about such decisions again.

I also think that, especially you as a computer scientist, should know that nothing beats a proper cable. Connecting the entire house wirelessly is becoming more unstable and slower, especially because there are more and more wireless technologies. For example, in the living room, you can set up a Fritzbox (there are apparently others as well) so that the phone or tablet can work, but I would only connect printers, TV, and possibly PCs via LAN.