The article had great advice on this actually. When asked how to get into C, or whether it was more advisable to learn Zig instead, Mitchell suggested that

It’s more important to learn how computers work and make the language just a means to understanding how they work. [...] even in this age of higher level abstractions and web development, it’s still important to understand the basics of CPU scheduling, memory, cache hierarchies, file systems, disc and file access. When you work directly above the syscall layer, whether in C, Zig or Rust, it really helps you understand what’s happening[...]