I may be mixing up things, but I have the feeling that this problem may be related to this: https://discussions.apple.com/thread/250715629
Since I upgraded to Catalina, I recurrently lose the ability to open pdfs in Preview. The solution indicated in the post works:
diskutil resetUserPermissions / id -u
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user
but it works for a few hours or sometimes days and fails again.
It is not always related to using Devonthink, but whenever I use it, the permissions problem comes back.
Thank you