Also keep in mind that any and all plant names added need to be in the context of POWO, per current site guidelines. So any of the Flora of China names that deviate from POWO would need some discussion first, which would be a roadblock to any mass import, unless you would be willing to have them go straight into synonymy with their POWO equivalents.
As others mentioned, iNat’s taxonomy has been built only as demand required. That said, if there were a particular group (genus or even small family) for which you anticipated new observations being added, you could always request those kinds of “batches” for curatorial attention. Or, consider joining the curatorial crew and helping out!