The FDA's purpose is protection of the public health. Drug approval would be one specific example. The SCCS (EU) evaluating UV filter safety is another.
If you know C well already, there is nowhere to go deeper systems-wise, apart from assembly. Maybe you mean higher as in more abstract? Rust is pretty abstract compared to C. Zig not so much by design. If you want to try something else entirely paradigm-wise, maybe something like Haskell could be interesting to you, or if type systems interest you, TypeScript's is quite sophisticated.
If you want to learn systems programming, I can recommend learning C. If you want to learn a programming language which allows systems programming, I guess Rust is not a bad choice. But it might be less helpful if the systems basics are unknown.
Imports are needed and important, not "bad". Most countries import goods. Why? Because not everyone produces everything. That is how society started and still works today.
I'm convinced naming things is equivalent to choosing the right abstraction, and caching things is creating a correct "view" from given normalized data.