Opening iCloud Drive files in Finder results in error “Couldn’t communicate with a helper application”

Had to downgrade from Sonoma to Ventura due to one application (LU Lite). Didn’t have a Time Machine backup from the older Ventura days, so restored from a backup when I was running Sonoma.

Most everything is fine, except iCloud files. You can preview them fine, but when you try and open it, you get the message “Couldn’t Communicate With A Helper Application”. I have tried all of this…

Logging out of iCloud and logging back in

Turning off iCloud sync on the Mac and turning it back on

Booted in safe mode

No impact. Anyone with ideas?

[Re-titled by Moderator]