There is no ARM64 release of Python for Windows right now, so unfortunately this doesn't constitute any kind of bugfix. We don't have a buildbot, and nobody out there has CI, so it's not a supported platform.

I get that it's easier to centrally fix all the third-party packages by changing the core library, but we've been saying for nearly 10 years that distutils shouldn't be used and shouldn't be assumed to be up to date. Anyone building on msvc9compiler.py has been broken since Python 3.5, because they've been using the wrong compiler.

A change to _msvccompiler.py for 3.10 can be considered, though you will need to get it ready before PEP 632 is accepted, at which point we close all distutils-related issues and only reopen for critical bugs.