Here is a detailed write-up on how to safely acquire the directly from Apple, along with methods to create the DMG file yourself.
. Official Apple DMG downloads for Catalina are usually limited to Update Patches download macos catalina 10157 dmg file hot
sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Catalina --nointeraction Detach and convert the result into a final on your desktop: hdiutil detach /Volumes/Install\ macOS\ Catalina Here is a detailed write-up on how to
This downloads the official installer (not a raw DMG) into your Applications folder. download macos catalina 10157 dmg file hot