[Solved] the feed lists package but multiple attempts to download the nupkg have failed

I consulter this case with our team and it looks like you were not able to download the package from Robot. Most likely due proxy/internet configuration. The workaround you have used works as the package might have been found by Studio on another feed and since the nuget folder is shared between Studio and Robot it will work. But this is not a proper solution as this can break if the nuget cache is cleaned.
You should download the specific package and place it on Orchestrator if you are not able to ensure proper connectivity to myget.org/F/workflow/