"Compress file" in Catalina sets wrong permissions on ZIP file
The Finder and Archive Utility are not broken; the change in permissions will be deliberate.


  It looks like something is broken in the Finder command an/or Archive Utility.app


Increasing Security

Apple's security engineers will likely argue that the new user only read write permissions, 0600, are correct and that zip is now wrong. Limiting default permissions is the direction macOS is heading.

Automator or AppleScript

Instead of fighting Apple, consider creating an Automator service or AppleScript to compress your files. You can then control the final permissions of the archive.