The correct package to deploy from is “webdeploy”! It’s downloaded as a pkg, which could look like a macOS installer pkg, but it is actually a zip-archive. Yes, even Cisco knows that if you need to cheat your download through web filters, you should rename your zip-archives to .pkg 😃

Rename the webdeploy pkg so it ends in “.zip”, then expand it, and go to the “binaries” folder. In here are the individual installer separated into dmg-files, so just grab the installers you need.