China has a million more soldiers than the US. The naval fleet is also larger.
War's of today would not be measured on number of soldiers. Even 100,000,000 individual soldiers would stand no chance against nuclear bombs or advanced tactical weapons like drones.
Also the US Navy is much larger and more advanced than China's Navy.
China has 1 aircraft carrier (that is a refurbished ship it bought from Ukraine) vs the US's 10 (which are all superior)
Other comparisons include US 3,700 aircraft vs 710 for China.
75 US submarines vs 70 Chinese
I agree with 2-0-Sixx that a war would devastate both countries and would most likely be the end of the world for almost everyone on the planet as result of nuclear fallout, etc.
But on a strictly numerical /theoretical comparison, the US military is far superior to China's.