How can one fully replace distutils, which is deprecated in 3.10? - python-3.x

Question

According to PEP 632, distutils will be formally marked as deprecated, and in Python 3.12, it will be removed. My product is soon going to support Python 3.10 and I don't want to put up with deprecation warnings, so I would like to remove references to distutils now. The problem is that I can't find good, comprehensive documentation that systematically lets me know that A in distutils can be replaced by B in modules C, D, and E. The Migration Advice in the PEP is surprisingly sketchy, and I haven't found standard documentation for distutils, or for whatever modules (such as setuptools?) that are required to replace distutils, that would let me fill in the gaps. Nor am I sure how to look at the content of the installed standard distribution (that is, the physical directories and files) in order to answer these questions for myself.
The "Migration Advice" section says:
For these modules or types, setuptools is the best substitute:
distutils.ccompiler
distutils.cmd.Command
distutils.command
distutils.config
distutils.core.Distribution
distutils.errors
...
For these modules or functions, use the standard library module shown:
...
distutils.util.get_platform — use the platform module
Presumably, that means that setuptools has either a drop-in replacement or something close to it for these modules or types (though I'm not sure how to verify that). So, for instance, perhaps setuptools.command.build_py can replace distutils.command.build_py. Is that correct? In any case, what about these?
distutils.core.setup
distutils.core.Extension
Furthermore, what am I supposed to make of the fact that setuptools does not appear under the modules or index list in the standard documentation? It is part of the standard distribution, right? I do see it under Lib/site-packages.
UPDATE 1: If setuptools is not currently part of the standard distribution, is it expected to become one, say, in Python 3.11 or 3.12? Are customers expected to install it (via pip?) before they can run a setup.py script that imports setuptools? Or is the thought that people shouldn't be running setup.py anymore at all?
Knowing how to replace distutils.core.setup and distutils.core.Extension is probably enough for my current needs, but answers to the other questions I've asked would be quite helpful.
UPDATE 2:
setuptools is indeed part of the python.org standard distribution, as can be determined by importing it from a freshly installed Python interpreter from python.org. The thing that was confusing me was that it is documented on a separate site, with a separate style, from python.org. However, as SuperStormer pointed out in the comments, some Linux distributions, such as Debian, don't install it by default when you install Python.
UPDATE 3:
This command:
Python-3.9.1/python -m ensurepip --default-pip
installs both pip and setuptools on Debian 10 on a Python installation freshly downloaded and built from python.org. Before the command is executed, pip is absent and setuptools cannot be imported.