Once the installer is sitting in your Applications folder, the goal shifts from downloading to deploying. Since you cannot simply "run" an installer to perform a clean wipe, you must create a bootable USB drive. This requires a flash drive with at least 16GB of space. Using the Terminal utility and the createinstallmedia command, you can transform that USB stick into a key that unlocks the installation environment. This step is the bridge between having the software and being able to install it on a blank hard drive.
Ignore "hot" download titles found on forums or file-sharing sites. They are typically clickbait or security hazards. Once the installer is sitting in your Applications
Compare the output with known good hashes (search online for "macOS Catalina 10.15.7 SHA256"). Once the installer is sitting in your Applications