To install install-rosetta-2 and packages, create a; Script, policy, add package's, to do it after enrollment is complete. This will work on Monterey 12.3-Apple Silicon and all others macOS and Intel. Here are some screen shots. Hope this helps you on you way. this is a generalization if more specifics write.
1) create your script
2) Create your policy
3)Upload your install rosetta 2 sh
4)Add all packages you need
Kudos for taking the time to polish those directions up, it can be missed by new admins so I'm sure it will help some out!
I currently use the Files and Processes payload on a policy triggered by Enrollment Complete. My first command is;
[ $( /usr/bin/arch ) = "arm64" ] && /usr/sbin/softwareupdate --install-rosetta --agree-to-license