You can write an unmaintainable fucking mess in any language. Rust won't save you from cryptic variable naming, copy-paste code, a complete absence of design patterns, dreadful algorithms, large classes of security issues, unfathomable UX, or a hundred other things. "Clean code" is (mostly) a separate issue from choice of language.

Don't get me wrong - I don't like this book. It manages to be both long-winded and facile at the same time. A lot of people seem to read it and take the exact wrong lessons about maintainability from it. I think that it would mostly benefit from being written in pseudocode - concentrating on any particular language might distract from the message. But having a few examples of what a shitfest looks like in a few specific languages might help