I mistakenly said Mojave in my previous post. It's Catalina:
Since installing Catalina I'm finding the when I create a .zip file with the archiving utility, I have to manually give other users permission to unzip the file through the Get Info dialogue. Big hassle. I can't find anyway to get around this.
Are you just looking at the permissions on your Mac running Catalina?
As this will show only you have permissions to read/write, with everyone as 'No Access', once you send the file to another user, they will also see they have full permissions and can unzip the file.
This applies to both Mac & Win users you give/send the file to.