Distance from sockets to the wall?

It is one thing to "once" place a box differently because that is exactly where it is needed. But it is another thing to place the boxes mostly outside the installation zones. In case of doubt, the builder will later claim he knew nothing about it, and the electrician has to redo the thing at his own expense because it is simply not "standard-compliant."

Basically, it is no different from telling the roofer to please cover the roof with bamboo because you liked it so much on vacation. Still okay for the tiki bar in the garden, but for the whole house from an electrical perspective a matter of legal protection. After all, usually more is at stake than just aesthetics and comfort. Consider a house resident unknowingly driving a nail in the wrong spot and as a result the house burns down. What do you think the insurance will say?

The installation zone runs through the room like a band, so you can't set incorrect distances. However, a 15 cm center-to-center distance should be maintained, otherwise it also looks bad.

What Lumpi says is what I would say too, because it just looks shitty if you slap them right up against the wall with only 5cm space.

The installation zone runs like a band through the room, so you can't set wrong distances.

Well, yes, but only outside of these bands. Here it was about the distance to a room corner, and there the band runs vertically with a width of 20cm and 10cm distance to the corner. A box with 15cm distance to the corner would therefore be inside the zone and thus okay, a box with 5cm or 35cm distance, on the other hand, would not.

Edit: Unless this box were inside the horizontally running bands, which run at 15cm distance from the floor or ceiling. Within these two 20cm bands, you could theoretically place the box directly in the room corner :-D