[I'm not recommending this, but maybe… No, no. I'm not sure…]

It isn't even just the newer shells that have solved this, zsh also has a solution out of the box¹. The extensive globbing support in zsh can largely replace `find`, and things like zargs allow you to reuse your common knowledge throughout the shell.

For example, performing your first example with zargs would use regular option separators(`--`), regular expansion(`{1..5}`), and standard shell constructs for the commands to execute.

I'll contrive up an example based around your file counter, but slightly different to show some other functionality.

    f() { fs=($1/*(.)); jo $1=$#fs }
    zargs -P 32 -n1 -- **/*(/) -- f

That should recursively list directories, counting only the files within each, and output² jsonl that can be further mangled within the shell². You could just as easily populate an associative array for further work, or $whatever. Unlike bash, zsh has reasonable behaviour around quoting and whitespace too.

Edit to add: I'm not suggesting zargs is a replacement for parallel, but if you're only using a small subset of its functionality then it may be able to replace that.

¹ https://zsh.sourceforge.io/Doc/Release/User-Contributions.ht...

² https://github.com/jpmens/jo

³ https://github.com/stedolan/jq