I don't support this idea of rewriting everything in Rust but the answer to your question should be fairly obvious. Rust that compiles will generally be stable assuming you don't do a bunch of unwraps and panics. C that compiles can seem fine until it isn't.

LLMs still aren't as good at detecting C memory management issues as an experienced developer. With Rust, that doesn't matter as much because generally the compiler will tell the LLM when it's wrong.