If a nuclear exchange happens, it doesn't matter what the per capita nuclear warhead statistic is, it just matters the total number of detonations. Warming is the same, the per capita CO2 emissions isn't important (other than for shaming purposes), it's the total emissions. Total emissions is what drives warming, not per capita emissions.
You seem to want to give China a pass because their CO2 per capita is lower than the US even though their total emissions is more than double, which kinda proves my point.
Qatar has the highest per capita emissions in the world, but they are 40th in total emissions. Drastically lowering their emissions will have very little effect on warming.
https://www.worldometers.info/co2-emissions/co2-emissions-pe...