There has never been any such thing as "total" hegemony, so that's a strawman argument. The US doesn't get much oil from the Strait of Hormuz and so while starting another war with Iran was a stupid move, the consequences are largely someone else's problem. I agree that depending on other countries for strategically critical manufacturing was a bad move. Fortunately that's now being rectified but it will take some time.

https://www.semiconductors.org/chips/

China's attempts at hegemony have largely consisted of making loans on bad terms to corrupt developing countries and then trying to foreclose when they don't pay. This has not worked.