How is a person being monitored on the Internet?

Question

System administration

Maybe someone works in the authorities or at the provider and will tell, if this, of course, is not top-secret information, about how a person is being monitored on the Internet, if there is an order for that? What happens, dns substitution for others, or just the provider redirects traffic, or how does it happen in practice technically and organizationally (what applications come to whom, etc.)? If there are detailed articles on the topic, I would be glad to have links.
The topic is interesting only for self-development. It became interesting to me here, but how does it even happen, after I found out that now this can happen without the permission of the prosecutor's office, immediately and by any operative, such as the latest news from Roskomnadzor.

Answer 1

For some reason no one mentions ICANN...
And of course I'm not an expert. But I'm just throwing facts from which you can blind noble paranoia.
- You are always connected to the network. Packets are sent all the time. Even when the device is turned off.
- There are well-known data transfer protocols. It is likely that there are unknowns.
- Windows is a closed source system. No one knows what she is doing there.
- Linux open system. But the possibility of introducing code that no one will notice, at the assembler level, exists.
- We all know about general-purpose computers. But not many people can imagine that there are computers or systems that are not even connected with transistors, created purposefully to solve one problem.
- On the open market, there are things like micro-SD that fit 64Gb of information in a section the size of a fingernail. And one can only guess what is not released to the open market and what other devices exist.
- The Internet is originally a military development. GPS was originally a military development. Rockets that fly into orbit are originally military development (although there may simply be coincidences).
The list goes on...

Answer 2

rutracker.org/forum/viewtopic.php?t=701670

Answer 3

fs.to/video/films/iLaQPbQVgVAyQoQFJ2gGcM-grazhdani...