Making an ISO file from an Apple provided DMG file?

I'd like to make a bootable ISO file from Apple-provided DMG file located under **Download macOS using Safari on your Mac** from: https://support.apple.com/en-us/HT211683 . They provide a DMG file with a pkg file inside which I used xar -xf on, leading to a: - Distribution (exec, 9kb) - InstallMacOSX.pkg (pkg obviously, 6.21 GB) - Resources folder (650kb) I'd assume InstallMacOSX.pkg is the most important, so it has these files: - Bom - InstallESD.dmg (6.2 GB) - PackageInfo - Payload (9 MB) (Renaming to .zip un'zips' a Install OS X El Capitan.app file) - Scripts How would I utilize 'Payload' and 'InstallESD.dmg' to make a bootable ISO file? Based off of this guide's end results, and my closest OSX version to this, I get these files: - .fseventsd - .IABootFiles (24.3 MB) - .IABootFilesSystemVersion.plist - .IAPhysicalMedia - Install macOS Sierra.app (5.03 GB) - Library - System (24.3 MB) - usr Install macOS Sierra.app has: /Contents/SharedSupport/InstallESD.dmg (5.01 GB).