how do i get my desktop NOT to be on icloud?

If you turned on the Desktop and Documents option and want to turn it off, see the following from Add your Desktop and Documents files to iCloud Drive - Apple Support

Turn off Desktop and Documents

When you turn off Desktop & Documents Folders, your files stay in iCloud Drive and a new Desktop and Documents folder is created on your Mac in the home folder. You can move files from iCloud Drive to your Mac as you need them, or select all of your files and drag them to the place you want to keep them.

1. From your Mac, choose Apple menu  > System Preferences. Click Apple ID, then click iCloud. On macOS Mojave or earlier, choose Apple menu  > System Preferences, then click iCloud.
2. Next to iCloud Drive, click Options.
3. Deselect Desktop & Documents Folders.
4. Click Done.

If you turn off iCloud Drive or sign out of iCloud, you have the option to keep a local copy of your files that are in iCloud Drive. Whether you decide to keep a local copy or not, a new Desktop and Documents folder is created in your home folder. If you choose to keep a local copy, your files in iCloud Drive are copied to a folder called iCloud Drive (Archive) in your home folder. Then you have the option to move any files that were in your iCloud Desktop and Documents, back to your new local Desktop and Documents.

Once iCloud Drive and desktops and documents box is turned as on see the article https://support.apple.com/en-in/guide/mac-help/mchle5a61431/10.14/mac/10.14

You can drag and drop few documents and not all of them to some other location see the last paragraph of the article https://support.apple.com/en-in/guide/mac-help/mchl1a02d711/mac

If you uncheck the box of desktops and documents .

It will prompt the items from this desktop and the documents folder are available in iCloud Drive , to remove items from iCloud Drive , move them to your desktop and documents folder on this Mac , click on show in finder .

Again open system preferences > iCloud > iCloud Drive > the box of desktops and documents box is unchecked , tap over the box to get it rechecked , a circle rotates setting up the box gets checked .

You will notice a folder is created literally on the desktop , tap it a pop up window appears the items on this desktop on this Mac have been moved into a new folder called “ Desktops - Apples Mac book …( the name of Mac will be written in the existing desktop folder in iCloud Drive , you can combine the contents of these folders any time , click on show in finder .

Right click on the folder created on the Mac and move to trash , restart the Mac and empty the trash , but again the documents are placed in a right place in iCloud Drive as well in iCloud server .

By unchecking the box of desktops and documents - the files and documents created are invisible temporarily both in iCloud Drive and www.icloud.com but they are not deleted from the server and still occupying the space , you can check the box and use get info https://support.apple.com/en-in/guide/mac-help/mchlp1774/10.14/mac/10.14 and delete the desired documents any where from iCloud Drive or iCloud.com and restart the Mac and empty the trash .

See the instructions for disabling iCloud Desktop here: Add your Desktop and Documents files to iCloud Drive - Apple Support