This tool [1] does the exact same thing - except that you nuke the chroot when you're done. And the reason is the same - to find all necessary dependencies. I had a small script that eventually became a Rust program. Then I kept adding features to it until it became what it is now. That's the reason why I never really got to explore the alternatives. Anyways, it's usable and nearly done.

Thanks for suggestion though. I'll take a look at it.

[1] https://crates.io/crates/genpac

[2] https://wiki.gentoo.org/wiki/Chroot_for_package_testing