icloud drive

As per this article https://support.apple.com/en-in/HT203052

Where to find missing files

When you turn on iCloud Drive, any documents that you already store in iCloud automatically move to iCloud Drive. You can see your files on iCloud.com, in the Files app on iOS 11 and later, in the Pages, Numbers, and Keynote apps, or in the iCloud Drive app on iOS 10 and iOS 9.

If you don’t see your files in any of those locations, set up iCloud Drive on all of your devices.

If you need to access a file that you deleted within the last 30 days, you can get it back from the Recently Deleted folder in the Files app, or on iCloud.com.

And you must see this article https://support.apple.com/en-us/HT206985

Do you see all the files if you go to iCloud.com/iCloud Drive using a computer browser?

Try going to System Preferences/iCloud and stop iCloud Drive syncing by unchecking the box. Wait a couple of minutes, then check syncing. Allow time for the  sync to complete.

Last resort  - have you tried signing out of iCloud and then sign back in?