So either we accept that they are governed by the dollar or not. Their values only matter in countries where they can take a non risk stand.
Do you mean it stops selling its products in China? Or stop assembling iPhones in China? Or both?
According to this page (https://www.macworld.co.uk/feature/apple/where-are-apple-pro...), 'the assembly of Apple's devices is for the most part done in China'.
If Apple leaves China suddenly, I don't think it can build that large an assembly line quickly to satisfy the global demand of iPhones.
And according this document (https://www.apple.com/newsroom/pdfs/fy17-q4/Q4FY17DataSummar...), half of Apple's Q4 2017 revenue come from iPhone. So, if the supply of iPhones is greatly reduced, the cash Apple sits on will quickly run out. Then Apple will be in great trouble.
The bigger issue is finding enough skilled people for the factories, China is pretty much the only place in the world with enough trained workers in the scale that Apple needs them.