Read Ray Dalio’s just recently release 576 page book “ Principles for Dealing with the Changing World Order: Why Nations Succeed and Fail” and you will get a far deeper understanding how he comes to that conclusion. I personally thought it is an incredible well researched book with lots of analysis including historical perspectives. Worth the read to understand the big cycles.
Rise to Globalism by Stephen Ambrose and Doug Brinkley is an adequate precis of US ascent to global power, which IMHO contains the seeds of its demise.
The Battle for the Soul of Capitalism, The Little Book of Common Sense Investing: The Only Way to Guarantee Your Fair Share of Stock Market Returns by John Bogle is the economic/fiscal/investing perspective I align with at the "non-billionaire" level.
China analyses is fluid at this time as you can imagine. Stay in touch with the usual The Economist, Bloomberg, Foreign Affairs, Parameters, and similar sources. IMO China's ascent and America's decline are both to a large degree psychogenic at this juncture, and a catalyzing condition to commit a path hasn't been developed yet.
eande's suggestion is good. If you find Dalio's theses persuasive, then I recommend you read his other three books to understand the quant angle he is coming from. You have to understand that as a billionaire, he can afford to be as much as a generation or even two off of his projections, and he'd still shrug that off. We don't have such luxury, so you have to be more discerning on his projected timelines, the numbers behind them, and the global market context it all takes place within.