To be fair, there is one shell that I think someday we could rely on. https://www.nushell.sh/ Besides that, my answer is "any programming language," since at the core, dealing properly with system calls and their outputs is the whole reason PL's exist. In practice, I've been using Rust lately which makes a nice systems language, but JS and Python are always options for shell-like scripts that don't suffer from quite the level of degeneracy when encountering weird filenames or unexpected input in general.
That would be a terrible shell. Changing directories, listing them, moving files, running programs are all simple no-brainer operations in any reasonable shell, but are non-trivial in any programming language that's not designed to be a shell.
So you use the shell for things that require no brain: browsing your directory tree, casual printing of files. Then, when you need to encode these operations in a script, you pull out a scripting language, because you need more than the shell can provide with its casual nature.
