Half of these are caused by C problems not present in Rust like: null pointer errors, buffer overflows, integer overflows.

The rest are logic errors (e.g., parsing errors) or crypto vulnerabilities (e.g., side channel attacks). There's nothing about Rust that magically prevents these errors. These vulnerabilities are discovered through testing and more importantly real world usage. Rustls has not been used nearly as much as or as long as openssl, so critical bugs could be in Rustls. You could encode some logic in the type system, but the types are still code that have to be tested. It's not a formal proof. It could still be wrong.

It depends on your threat model and your risk tolerance whether you want to depend on relatively unvetted code.