in icloud drive only showing waiting to upload

For a device, try Settings/Your Name/iCloud and slide off syncing. Wait a few minutes and then resync. This will start the sync from the beginning.

For a computer, try going to System Preferences/iCloud and stop syncing by unchecking the box. Wait a couple of minutes, then check syncing.

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