Eventually a message “Are you sure you want to download macOS Monterey” will appear.
Follow the Mac App Store link through Safari to open the Mac App Store on the Monterey page.Follow these steps to download macOS Monterey (or other versions of macOS below) from the Mac App Store:
Apple only replaced Monterey with macOS 13 Ventura in October 2022, but you can still download the installer for Monterey from the Mac App Store.