CNY displacing USD would entail allowing people outside China to buy really significant quantities of CNY-denominated financial products. This would entail CNY/USD changing so CNY is more expensive, because the default currency for financial products currently existing is USD. Which would slap a corresponding huge price increase with 0 increase in quality to all Chinese export. Which would murder Chinese manufacturing export. Which would entail laying off some grand proportion of an industry that employs 5% of the _human_ race. Which is why they're not gonna do that.

I don't think China wants to make the CNY the reserve currency because it would decimate China as a manufacturing hub. They prefer China to be Jakob to the U.S. being Esau. The red lentil soup can be quite bitter.

Is China still rising or already in decline?

I’ll believe it when I see it, there’s a spread between onshore and offshore yuan exchange rates due to currency manipulation. It becomes harder to manipulate a currency as more of it is created, and AFAIK countries are not loading up on Chinese govt debt, but I may just be unaware?

The USD hegemony isn’t because of oil, it’s because everyone wants dollar-denominated assets. Treasury bonds, US real estate, US equities, etc. Possibly Chinese exports could soak up some of the yuan demand?