Note that while the chart Bloomberg used makes it look like the Yuan is poised to take over from the dollar, it's not. It's gone up... to 2.69%. This is how the currencies stacked up in Q4 2022 according to the IMF[0]:
* the US dollar (58.36%)
* the Euro (20.47%)
* the Yen (5.51%)
* the Pound (4.95%)
* the sum of all currencies not in the top 8 (3.45%)
* the Yuan/Renmibi (2.69%)
* the Canadian dollar (2.38%)
* the Australian dollar (1.96%)
* the Swiss franc (0.26%)
So it's not that the Yuan is becoming the world reserve currency, it's that countries are avoiding relying on a single reserve currency. The lesson from the Ukraine sanctions wasn't to avoid the dollar, it was that relying too much on any outside country's currency puts your sovereignty at risk, so they're diversifying.
If you look at the chart in the link below, the gains from the dollar's loss are spread out pretty evenly.
[0] https://data.imf.org/?sk=c22e624f-ce09-4c9e-a70b-647defa5215...
Whenever country like Japan stops using dollar to settle oil purchase, it is another step. With currently development around the multi-polar world, it is likely not one single currency, rather several regional block reserve currencies will arise to replace the Dollar.
You're just assuming that China would let people leave the country with their wealth. Are you forgetting that countries have control over their borders and how finances are handled?