This idea builds off of this other idea https://community.esri.com/t5/arcgis-online-ideas/allow-tying-arcgis-online-and-arcgis-enterprise/id... .
Once ArcGIS Online and ArcGIS Enterprise are linked together allow transferring content to users on the other platform. Even better would be adding the ability to check any dependencies on the items being transferred and updating sources to point to the new location.