Zig is way more low level. Nim is a great alternative though. 90% of the performance with 50% of the work.
There is no more low-level. Rust and zig can express the exact same programs. Rust just catches a few more erroneous ones at compile time, but you have to manage memory explicitly in both.
Zig doesn't even have a string type. It's not an alternative to Rust, which is meant as a safer C++.