This is huge news for me. They were always swimming in export profits / probably still are / travel limits since COVID means that obvious leak of travelling and spending abroad is plugged.
How could they run out of cash?
...
In any case, Yuan is the new foreign currency. And China has, well, all of it...
Higher reward, similar risk, still perfectly reasonable USD FX reserves.
Economically, demographics are insanely against China and it is not clear that immigration is a viable way for them to close that gap.
Finally, their unique political system has not been tested during a period of low growth. It is not clear they have the political stability to be a reserve currency. Again, the US has been pushing their luck.