I don’t think China, or any other nation on Earth, wants to be the defacto reserve currency.
Many actors like China want an escape route to SWIFT, but beyond that, they’ll be very pleased with a multipolar solution.
China, if nothing else is student of history. They know the stress of becoming an existing reserve currency for the United States, Great Britain and British Pound, Spain, etc. It is both a great privilege and a terrible burden at the same time.
They don’t want that. They can be delighted to see the headaches it causes for the United States. They want to be in control. One way to advance their claims against Taiwan without the SWIFT ban was wasted on their newly formed state capitalist superpower.
And yes, it’s the perfect tool for social and political coercion in the country. China is the first China. The uniformity between the US and the dollar is secondary as it relates to the US’s strong use of SWIFT and how it can hamper their domestic and regional policy goals.