hdiutil convert ~/Desktop/Ventura.dmg -format UDTO -o ~/Desktop/Ventura.iso Rename the resulting .cdr file to .iso :
hdiutil unmount /Volumes/Install\ macOS\ Ventura Convert to ISO (hybrid): Download Macos Ventura Iso
sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/Ventura --nointeraction Wait 10–20 minutes for it to finish. Unmount the volume (but keep the .dmg file): hdiutil convert ~/Desktop/Ventura