Earlier quoted context omitted.
I don't think spending more on military than the next 10 countries combined can be described as "only" in any way. The highest spender are the US, with $732.0 billion, followed by China with $261.0 billion, then India and Russia with $71.1 and $65.1 billion respectively.
Militaries are reliant on domestic production and labor. (Paying Chinese solider costs the government a fraction as much as an American soldier.) So instead of an exchange rate conversion, you should be doing a purchasing-power conversion. For these three countries, that means multiplying by 2x to 4x. Also, the US is particularly inefficient at capital spending. It costs us a billion dollars to build a mile of subway…
Where did you get those numbers from? According to the OECD the renminbi PPP rate is 4.198 whereas the the current exchange rate is 7. That's 1.67x not 3x.
https://data.oecd.org/conversion/purchasing-power-parities-p...