I would suggest that the FAA will soon issue an AD saying that any maintenance by a Russian MRO on a Boeing airplane since the start of sanctions will render the C of A invalid. There are a lot more state responsibilities other than checking the airplane registration. I would be very surprised if China would be willing to risk their global access to airspace by allowing Russian owned stolen Western airplanes which are demonstrably not airworthy, to operate in their airspace.
China is Russia’s friend until there is a cost to them, then all bets are off