Can we migrate the data directly to Esri UN model geodatabase instead of migrating to Asset Package GDB, using FME Desktop?

Hello @ni3​ 

You can move data to the Esri UN data model once the UN is fully published/versioned. To do so, you have to use the Esri ArcGIS Portal Feature Service Format. This will allow you to read/write to the UN including the Branch Version of your choosing.