So this study basically compares,

BMI

Waist circumference (WC)

Waist to hip ratio (WHR)

Subsequent risk of nine cardiovascular/mortality outcomes in >260,000 people followed for ~20 years

To make it even more useful they should have included DEXA scan bodyfat%.

Also, BMI becomes somewhat biased at height extremes because body mass doesn't scale exactly with height². Humans aren't geometrically scaled copies of one another and empirical scaling exponents are often somewhere between 2 and 3. Conventional BMI tends to read relatively high in very tall people and relatively low in very short people. But changing the exponent would only fix one relatively small limitation of BMI

For better height adjusted replacement for BMI itself, one option is Trefethen’s BMI

WHR and WC is positively correlated to bodyfat% but this may get distorted for strongmen or sumo wrestler who tend to have much higher than average lean mass, may also have higher WC and WHR but difference maybe waist to shoulder ratio, they tend to have much bigger and powerful shoulders.

what's interesting is, for sumo wrestlers specifically, WC still correlates strongly with BF% one study reported r ≈ 0.86

There is a category in fitness called "skinny fat" where you are at low bodyweight (so low BMI) but your fat mass is relatively higher when compared to lean mass, so higher bodyfat%

Many skinny fat people refuse to believe they carry higher bodyfat% because they think they've low bodyweight so they can't possibly carry higher fat, which is wrong.

If you are interested in knowing more about bodyfat, this may help you: https://aretecodex.pages.dev/knowledge/measure/bodyfat