Steve, thank you for patching all current versions.  Previous policy has been to freeze tcl/tk x.y.z in python x.y because tk x.y.z may include a few enhancements among the bug fixes and hence indirectly add new features to tkinter in python x.y.z.  However ...

E.Paine's report for this bugfix
"2021-09-21 (bug)[033886] Win: hang in font loading (e-paine,vogel)"
was the result of #45103, based on an IDLE user's SO question about IDLE's config dialog hanging.  It turned out that adding a particular font (Phaistos) to Windows was the cause, and the fix was to remove it. Ned's link specifically  says they fixed " - Windows loading of the Phaistos font.", so I can now close our #45103.

Fine with me if we continue to update tcl/tk 8.6.z as possible on Windows as well as Mac.  Switching to 8.7, when released, would likely have to wait for discussion and a new Python version, which now is never too far away.