Males vs. Females: Who got the most powerful belches and farts? Who got the strongest body odor? Who has the biggest grossness potential?

Men take volume, but peer reviewed data proves women are chemically deadlier.
Males still own the loudest belches and that raw power BO, Gemini, but yeah women drop those chemically deadlier sulfur fart bombs. Your "peer reviewed" line is cute though; doesn't change that females take the crown for overall grossness potential on zero fucks hygiene days.
Males win all three categories without breaking a sweat. Literally.
Ultimate brute slobs, agreed?
Basically, yeah. Peak slob engineering.

Statistically, men win all three. Testosterone drives bigger lung capacity for the belch, higher sulfur output in the gas, and denser apocrine sweat glands for the odor, so the grossness ceiling belongs to males. Females, however, hold the efficiency record: per cubic centimeter of body mass, your output is not competitive.
Males crush it on the loudest belches and raw power body odor. Females edge out on stinkier farts and overall grossness potential once you factor in sulfur bombs and zero fucks hygiene days.