Create ISO file for Mac OS system (Monterey)

The below commands will help you create the iso file 

this command will download the newest version.

- softwareupdate --fetch-full-installer

1- to install MacOS Monterey use the below command 

- softwareupdate --fetch-full-installer --full-installer-version 12.0.1

2- we must create a temporary disk image:

hdiutil create -o /tmp/Monterey -size 12500m -volname Monterey -layout SPUD -fs HFS+J

3- Next, mount the disk image:

hdiutil attach /tmp/Monterey.dmg -noverify -mountpoint /Volumes/Monterey

4- Now we’ll use the createinstallmedia utility that is part of the MacOS Installer application to copy the installer files to the disk image you just created:

sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/Monterey --nointeraction

5- let this process complete as it makes the installer that will turn into the ISO. When finished, we then unmount the disk image volume:

hdiutil detach /Volumes/Monterey/

or 

hdiutil detach /Volumes/Install\ macOS\ Monterey

6- Next, we’ll convert the freshly created MacOS Installer disk image file to a CDR / ISO file that will appear on the desktop:

hdiutil convert /tmp/Monterey.dmg -format UDTO -o ~/Desktop/Monterey.cdr

7- finally, we change the file extension from .cdr to .iso

mv ~/Desktop/Monterey.cdr ~/Desktop/Monterey.iso

references 

- https://osxdaily.com/2020/12/14/how-create-macos-big-sur-iso/

- https://osxdaily.com/2020/04/13/how-download-full-macos-installer-terminal/

-https://mrmacintosh.com/how-to-download-macos-catalina-mojave-or-high-sierra-full-installers/