Just give the LLM requirements and have it output rust. Just like giving a compiler a text file and it outputs machine code.

Theoretically the LLMs could go straight to machine code. No need for any intermediate language. However, the HN stories have made it clear that LLMs are not great at going directly to machine code or Rust. Rust is, time and time again, only being used as an optimization intermediary. If LLMs were better to target it directly they wouldn't be always be stories about translating to it from another language.