WW3 already started via attacks upon Ukraine and Middle East. China and US cannot fight directly and so are fighting via proxies. They cannot declare open conflict because in the case of US it would paralyze so many large US corporations via the Trading with the Enemy Act. Days before the Ukraine invasion China and Russia signed a treaty guaranteeing mutual support of their ambitions in Ukraine and Taiwan. https://www.newyorker.com/news/daily-comment/russia-and-china-unveil-a-pact-against-america-and-the-west Iran and Russia are only still viable economies moreover capable of significant military aggression because of Chinese enabling ongoing trade (primarily but not only oil/gas sales) despite US sanctions in the case of Iran going back more than a decade. China is openly challenging US hegemony and it gets cheap oil and captive markets for many of its manufactured goods into the deal while US pays a high price to support Ukraine and Israel. Losing/surrendering the oil resources of Iraq is another US loss in this unfolding war between USA and China over global resource hegemony.