how can I download Catalina without app store
The System Preferences -> Software Update has failed more that once. I just want to download the DMG file or the APP file. Is that even possible?
iMac 27″, macOS 10.15
How to get old versions of macOS - Apple Support
If you need to update Catalina and Software Update isn't working for you, https://support.apple.com/downloads/macos