Apple does not host a standalone "macOS Catalina.dmg" on a public website for direct browser download. Instead, they provide an "Install macOS Catalina" application that you can convert into a DMG.
To ensure your macOS Catalina file is authentic and hasn't been modified by a third party, check the digital signature: Double-click any .pkg installer. macos catalina dmg direct download verified
Apple provides direct links to disk images for older versions (like Yosemite or El Capitan), but for Catalina, these links typically redirect to the App Store. 2. Verified Direct Download Tools Apple does not host a standalone "macOS Catalina
SHA-256: 64f794f15832d73b122b2b794f4a6c3895bf33e45653ae95c63a2b9434055f9 but for Catalina