Problem finally resolved on my PC, Windows 10. After trying all the above, including resetting my computer to a previous date (which didn't work), I finally looked at my apps. There it was... a new microsoft app was installed in late September 2023... MICROSOFT 3D VIEWER. It was either automatically installed with an update, or I selected it as an optional app that I made the mistake of saying "install."
Anyway...i deleted it and now everything is back to normal on my desktop icons.
Hope this works for you guys.