I honestly don’t know what settings it could be, but for what it’s worth here is the “old thread” back when we were discussing how to make those Huanyang VFD work:
My suggestion would be to go down the list of VFD params and do a side by side comparison with the value on yours (not saying they should be set to the values in that thread, but it may allow to spot something to investigate)
My other suggestion would be to do a factory reset then reprogram the values you need: sometimes we THINK we have them all under controls, but we don’t.
Good luck, I feel the pain of being so close yet not quite there!