It is the belt most likely and thats where i would start as it probably the least expensive component of the drive system.
I checked gates, and they only make a belt for the Hisun Tactic 400 or Early strike models.
MotorcycleDoctor is pretty much the best source in the States for Hisun parts, have a look at this one
https://www.ebay.com/itm/201453293033?hash=item2ee78d4de9:g:z8oAAOSwo0JWKB9b