disappearing icons

Can you see them when you open a Finder window and select Desktop in the sidebar?

If so, then see > Ways to organize files on your Mac desktop - Apple Support

If not, then perhaps you are logged into a different user account or inadvertently moved them to the Trash.

I've been using Mac's for 30+ years and desktop icons do not just disappear on there own.

Have you tried using a Spotlight or a Finder Search, to look for the misplaced icons by name?

the name of the file(s) that are missing from your desktop.

I am having the same problem, and no, can't see them in their regular windows or on the sidebar.