See discussion in #4101 (comment)

Runtime is the remaining repository that publishes differently when building the repo in isolation versus when building inside the VMR. The VMR publishing is also missing some artifacts, i.e. checksums, version files and potentially more.

This item tracks getting rid of prepare-artifacts.proj in runtime and using the Arcade publish entry-point. Presumably this just means following the already established process from windowsdesktop and deployment-tools: dotnet/windowsdesktop#4251