Hi there, Traintrack.
I see that you're unable to access the files you're syncing in iCloud Drive on your Mac since upgrading to macOS Catalina. I'm glad to help.
Set up iCloud Drive -- Make sure that iCloud Drive is turned on. You'll find the location of the setting under "On your Mac”. If it’s off, turn it on and see if your documents sync. If it’s on, turn it off and restart your Mac: How to turn your Mac on or off . Once you’re back to the desktop, turn iCloud Drive back on and see if you files sync now.
Use safe mode to isolate issues with your Mac -- Restart your Mac in safe mode and test how it responds. If it works while in safe mode, reboot normally and test again in your own user account. If not, continue to "How to test an issue in another user account on your Mac" below.
How to test an issue in another user account on your Mac -- If the issue is also happening in safe mode, use this article to create and test a new administrative user account. This will demonstrate if the issue is isolated to your account, or if it's system wide.
Let me know how that goes, and take care!