Well, for that to happen... other countries currently supporting the US Dollar would have to agree to that and pledge their support for the Chinese Yuan or the digital equivalent of it.     China being a communist country with an oppressive government will not count in their favour to get other countries to agree with that.

China are one of the biggest economies in the world currently and this fight would be very interesting to see.  Who would be able to influence other countries to accept their currency as the global reserve currency.     I think a lot of the communist countries might support China and the capitalist countries will still support the US Dollar.