Safari File Dialog Fails to Show
This is now fixed in the latest Safari update, 14.0.3.
More information here https://macintouch.com/community/index.php?threads/problems-with-safari-14-0-2.2926/
And here: https://mrmacintosh.com/security-updates-2020-001-for-catalina-2020-007-mojave-safari-14-0-2/