I use macOS Monterey, and my problem appears to be similar to
but the solution there (giving ruby full disk access) doesn't work.
When I try to open a file in Desktop (/Users/yourname/Desktop/ ), the emacs minibuffer shows "Reading directory: Operation not permitted, /Users/yourname/Desktop/".
I've already given full disk access to Emacs.app and ruby. Indeed emacs Dired can list the contents of any directories (/etc/, /usr/, . . . ), except for Desktop.
Desktop can be accessed by other applications, like iterm2 and GIMP, which I've given full disk access to.
This may be related to the cloudification of Desktop, but I haven't been able to find discussion that seems to be related to my problem on the Net.