Starting with knowledge of another statically typed language, Rust really isn't that hard. Borrow checker gymnastics take a few days to get over after which one can get relatively productive. There's plenty of code samples on GitHub and mature crates to get going on the db and web layers.

As a primarily Python programmer, I did not feel over-burdened by learning Rust. Sure, I never learned how to deal with lifetimes, never wrote a macro, and probably used clone a few places where I did not have the need. I was almost certainly leaving performance on the table. Yet the language gives you so many guardrails that I always felt like my code was doing the correct thing.

I thought the same thing. Either he means that he learned the very finer parts of Rust on the job but knew it well to begin with. OR. He was really doing 40 hours of work and 40 hours of Rust learning per week. Which is fine too, as he delivered.

Have you tried it? I don't see any rust code in your github profile.

Personally, I don't think it's that bad. I did it in 2020, and thought it was (mostly) easy. A few weeks of wrestling with the borrow checker until I finally "got it". I now work in Rust full-time.