The US has the most advance tech and the largest budget, nobody can deny that. But how useful are these when something like the B2 cost billions and there is only one tank factory in the entire country? Also, many critical parts for these expensive war machines are difficult to source and easily disrupted by an adversary.
One example is the artillery ammunition being supplied to Ukraine. The US can barely break 50K/month. Meanwhile, Russia is producing them by the hundreds of thousands. China is even higher.
The US has the fanciest toys but those can barely be made and are only good for strategic, precision attacks; and their supply chain cannot sustain a prolonged conflict. In a peer conflict, these are fatal. If China started a war, their manufacturing base can potentially pump out more weapons than the US can destroy. And in the long term, the US may not be able to keep up in both weapons and personnel.
Just like how Japan got the largest and most advance battleships with the more experienced crews at the beginning of WW2 but still lost to the US. Japan could not match the production and rapid replacement rate the US had. Now, the US is in Japan position compared to China.