I agree that having to remember is a problem, it's one of the many shortcomings of C that it doesn't let you differentiate between types at compile time.

Pointing into subsections works fine. You just have to create a type for it. This solution doesn't have the same problems as strings because you don't rely on a terminating entry, and it's what languages like Rust or Java do as well.

You can allocate dynamic arrays on the stack in C just fine with alloca(). The only performance cost is when checking bounds, but since it's a dynamic array, it's the same cost you'd pay in Rust.