It couple physically disable camera + mic + whatever, and ALSO have hooks that enable you to do extra things with it in software?

Why don't you work on improving rsync, rather than reinventing the wheel? Or create something new??

It's fine as a personal project, but as soon as you get other people using your new code, they'll be exposed to all the bugs that you are inevitably creating.

Honestly, this kind of "rewrite something battle tested in my favourite language" project is dangerous and insane.

C++ destructors are implicit, while defer is explicit.

You can just look at the code in front of you to see what defer is doing. With destructors, you need to know what type you have (not always easy to tell), then find its destructor, and all the destructors of its parent classes, to work out what's going to happen.

Sure, if the situation arises frequently, it's nice to be able to design a type that "just works" in C++. But if you need to clean up reliably in just this one place, C++ destructors are a very clunky solution.

Example: If a build is going on in the background, I can see when it stops.

Windows XP was a disaster. Resistance to adopting it was industry wide, and lasted years. It was only with Service Pack 2 (which was an enormous rewrite of basically the whole system) that they started to turn the ship around.