Well, the said 'war' between these giant countries has been known even before. They both have huge resources and intel, but we know US still ranks no. 1 in the economic label (if not shaken by the pandemic). So China, being a competitor, knows how to attack. And I think, China need not to 'hack' Bitcoin. Most of us are aware with the fact that China had the plans and independence to use blockchain, and create their own cryptocurrency. Though, there are users of Bitcoin and other cryptos in their country, still, they saw a great opportunity with these coins, and to be able to defeat US in terms of the economic ranking, well, they have their own method.