Spot lighting / arrangement / quantity

For me, a 50 EUR surcharge from "normal" Schuko to Schuko with USB. I’d rather get that myself somewhere else...

May I ask a "stupid" question, can the sockets then basically be switched from normal to USB just like that, without anything in the basic wiring needing to be considered beforehand?

To my knowledge, yes, although I wouldn't put my life on the line for every product on Alibaba or every old building wiring from 1946. Yours, by the way, neither....

And motion detectors / presence detectors indoors? Has anyone already had experience with that? I would find that super clever in the hallway and in the basement

May I ask a "silly" question, can you basically just switch the sockets from normal to USB without having to consider anything in the basic wiring beforehand?

Yes, you can. I have installed several at my place. A normal socket costs about 3-5 euros and with USB about 50 euros. At least with the Jung AS500 series. I can't imagine just 10 euros for a USB socket.

What is the difference between presence detector and motion detector?

Presence detectors actually detect the presence of people, because in many models even the movement of the respiratory system and shoulders is sufficient to determine this. Motion detectors, on the other hand, are detectors that require larger and stronger movements to be activated.

...
I can't imagine only 10 euros for a USB socket.

About 14 months ago, I bought some for 17 euros at the "biggest river". Since these sockets with two USB ports are not immediately visible, they did not have to fit exactly into the series.