every array access and string comparison is a potential vulnerability in C. I'm not saying that in practice, all of them will be vulnerable, just that every one of those is a place where you could miss a check and end up with a memory bug.
That's kind of a disingenuous way to reason about it. You absolutely can bounds check your memory accesses in C, and bounds-checked accesses are as safe in C as they are in any other language.
the point isn't that it's impossible to write C that's safe, it's that doing so requires 100% success rate of a human implementing something correctly. furthermore, the main cases where C can get a performance benefit over safer languages are where there is a complicated invariant that ensures safety. the problem is that these are incredibly easy to break during refactoring, or when a different dev modifies the code later. compilers are much better then humans at verifying that code is correct.
If that is what your C code looks like, then yeah, you should probably not be writing C code.