Sorry for the late reply. If you are looking to import data, please check to see if the compaction parameter in the storage configuration is turned off, as performing compaction-related operations during data import can affect speed.
Additionally, importing data when indexes already exist will reduce the import speed.
If you're importing data without indexes and without compaction, you might try adjusting the batch size parameter in the Nebula importer, as it can affect the speed of the import.