The Gnome developers believe that users should not use the desktop as a launchpad for launchers. In order to enforce this belief, they disabled Desktop Icons on Gnome Desktop.
To the best of my knowledge, they are the only desktop that has done such enforcement. Even Windows doesn't.
To this end, independent developers created a Gnome Extension to restore the functionality of using Desktop Icons on Gnome. Zorin OS uses one such extension.
Many extensions are really great and some are quite imaginative.
But it is important to remember that Gnome Extensions are not supported by Gnome and could be rendered inoperable by an upgrade from Gnome. They are independently made, so may not always work as fully as what used to fully work on a standard system desktop environment.
It sounds like you are running into an issue with the desktop extension from your description. You might try reinstalling it:
sudo apt install --reinstall gnome-shell-extension-zorin-desktop-icons
Or it may be that in VM, there is another issue interfering with the extensions performance.