Can I ask how methane is a net emission with water and carbon dioxide? They all affect the planet differently while also being "GHG emissions"

I'd also like to add after thinking about it how the location of these emissions also matters. Jet planes have a larger impact with their emissions over other travel in part because the higher altitude increases the greenhouse potential of its emissions. So again, if we just count "GHG emissions" as if the tons of GHG emitted is the only factor not the duration the gas exists in the atmosphere, the location of emission, or if it is dumping sequestered carbon.

Because if we look at how cows produce methane, it's the bacteria in the cow's stomach that produces that methane, bacteria that would produce methane on rotting biomass as well. What's the actual net difference between natural decay and accelerated cow digestion. There's lots of agricultural produce like bananas where a meaningful amount of production goes to waste and decays. Is this waste and the emissions that happen from the waste accounted in the "GHG emissions" of eating bananas?

This is all before getting into weird GHGs like sulfur hexafluoride as it has a global warming potential 23 thousand times higher than carbon dioxide. So are we counting it by the ton as if it is the same as carbon dioxide by the ton?