setuptools was never part of Python's standard library. I think you're thinking of distutils which was removed from Python in the 3.12 release. You can easily access distutils again by installing a package from PyPI.
You are right, it was distutils. Good call out. Not sure why I thought of setuptools.
This comment thread is a microcosm of the problems with python packaging :D I appreciate the work the ecosystem does on it and everyone is doing their best, but its still a hard problem that doesn't feel solved