You seem to have a very idealized idea of how selfless this whole thing is. Google has sponsored a lot of work in the kernel, so have multiple corporations over the years. This is not some puppies and raibows shit here.
It just happens to work really well because the license and multiple interest of a good kernel do just that: a good kernel.
Surveillance issues and too strong corporations are an issue with your government, not the kernel
Seconded. I have worked on linux for 15 years doing software dev and some IT. Nobody knows that stuff in detail unless they have to because of some arkane deployment reason. Any half good local llm will be miles ahead of most books. Tell it what you need, it will spit out some code, understand the code and ask it or search online how it works exactly. Rinse and repeat.