When it comes to debugging Rust in VSCode, the CodeLLDB extension provides a great debugging experience. Until you try to step into some Rust stdlib code and are greeted with assembly.
Of course you can manually add a source map entry for your rust toolchain, which involves finding the current rustc version commit hash and the sysroot path for the source code:
$ rustc --version --verbose
rustc 1.76.0 (07dca489a 2024-02-04)
binary: rustc