I think learning a language is not the point, but learning underlying system (OS) is. What you want to learn (especially in embedded world) is how various Linu

I think learning a language is not the point, but learning underlying system (OS) is. What you want to learn (especially in embedded world) is how various Linux/POSIX APIs work, not language features. So either choice is good as long as you learn to use them, but I personally recommend C because C is the first class language for Linux APIs e.g. they are exposed directly via #include <sys/> or #include <linux/>. As others recommend, you can learn C and Rust at the same time though.