Desktop picture changes on it's own.
I am user of Monterey 12.6.3 and my desktop picture changes on it's own and there is this old solve:
”Try deleting the Desktop settings file. Open a Finder window, select Go
menu (on the menu bar) > Go to Folder, and type
~/Library/Preferences. Then, delete "com.apple.desktop.plist" and
"com.apple.systempreferences.plist", and restart. Finally, change your
background”
Problem is: I just don't find any "com.apple.desktop.plist" named file from my Preferences folder.
MacBook Pro 16″, macOS 12.6