Not wanting to invest time makes sense, but I think you'll definitely get return on investment by learning C. It's doesn't end with rust. Learning C's approach to memory will give you a much better understanding of pretty much all object oriented and imperative languages and give you a better understanding about how memory might be used under the hood in higher level languages in general.

It won't take you too long either! Compared to modern languages, C is very small and very simple and likely won't take as long as learning any other popular language in use today. You can learn all of C in the amount of time it takes most people to learn just the basics of a borrow checker. If you only focus on the aspects related to memory (stack, heap, sizing, arrays, pointers) it would likely only take half a day, if that.