Execution of water pipes / technical room

yes exactly, and if there are problems somewhere later on....then you get to "fiddle" nicely with the installation...

There are also things like installation guidelines...and distances to sockets...

Then why don't you name the mistakes to the OP :)
One shouldn't fiddle by themselves anyway.
Well, I'm not a professional in this matter here, most people here aren't... but honestly: my controlled residential ventilation (of course not wrapped like that, but in blue plastic) didn't look any different to a layperson on the raw ceiling....
And in my old basement - which I don't like to remember because of the basement - it also looked like that from memory.

Hello,

we are building a prefabricated house. Regarding the execution of the sanitary installation in the technical room, I would like to hear your opinion on what you think about it.

To me, the routing seems somewhat unorthodox, which suggests that the pipe runs could not be combined in the shortest way, but rather larger distances had to be bridged.

Rhenish greetings