One-shot, no, but there are a bunch of people pretty much solo-building their personal ideal language with AI and it's going quite well. You need to know just enough about language design to be dangerous, but you don't need to be a seasoned pro.

I'm doing it myself: https://zena-lang.dev/

It seems like such a strange thing to do, building a language that you aren't going to write by hand. It's guaranteed to perform worse at higher cost, fill up a lot more of the context window, and burn a ton more reasoning tokens.

If you're using AI, a language with a large training set is going to win.

Been thinking about doing this myself (did some PL in grad school but it's been a long time), but I find myself wanting to reach for a Scheme (using macros to grow the language I want) and customize it or build something atop Janet.

Curious why you wanted a more ML / Rust / Scala inspired syntax. (Personal preference here is totally valid btw, just curious.)