Hi Julius,
As Derek mentions, you can use distributed collaboration to share data from ArcGIS Online (where you are exposing the data using Hub) back to ArcGIS Enterprise - so long as your ArcGIS Enterprise version is 10.5.1 or higher. Here is a quick blog on enabling collaboration: https://www.esri.com/arcgis-blog/products/arcgis-enterprise/sharing-collaboration/distributed-collab...
If you want to share the data as a copy to ArcGIS Enterprise, you'll need to have sync enabled on the layer (on the layer details page, select the Settings tab > Enable Sync (disconnected editing with synchronization)). Only the source can sync edits in collaboration. For example, if you share from ArcGIS Online > ArcGIS Enterprise, any edits made to the layer in Online will sync with Enterprise, but if edits are made to the layer in Enterprise, they won't sync back with Online.
Hope this helps; let me know if you have any questions,
Hilary