safety-wise, zig is better than C because if you don't do "easily flaggable things"[0] it doesn't have buffer overruns (including protection in the case of sentinel strings), or null pointer exceptions. Where this lies on the spectrum of "C to Rust" is a matter of judgement, but if I'm not mistaken it is easily a majority of memory-safety related CVEs. There's also no UB in debug, test, or release-safe. Note: you can opt-out of release-safe on a function-by-function basis. IIUC noalias is safety checked in debug, test, and release-safe.

In a sibling comment, I mentioned a proof of concept I did that if I had the time to complete/do correctly, it should give you near-rust-level checking on memory safety, plus automatically flags sites where you need to inspect the code. At the point where you are using MIRI, you're already bringing extra stuff into rust, so in practice zig + zig-clr could be the equivalent of the result of "what if you moved borrow checking from rustc into miri"

[0] type erasure, or using "known dangerous types, like c pointers, or non-slice multipointers".