Honestly everyone is concerned about zf qc. And I have to say my 3777-06 have some small qc issues date alignment, case finishing and marker alignment but noting that you can see on the wrist. But the only a7750 doa I got is a v6f (tag heuer). I sent to factory it was fixed and dead again after one month.
I suggest to you not to bother to send to China. Be happy for the perfect cosmetic quality and have the movement serviced or upgraded to swiss.