The string bikini that was popular in the 80s through the 00s usually isn't flattering on most body types or on a body in motion. Even when I had a BMI of like 18 those things would flatten my breasts downward, give me back rolls from the tiny straps that need to be pulled tight to keep the thing on, and for whatever reason never covered my actual vulva, looking like I had two sets of labia majora. Even a standard "bikini" depilation routine isn't sufficient... You would need to remove basically all the hair for none of it to be visible.

Since I had a kid I wear one pieces with trunks and I don't even have stretch marks or ab separation. I can't even imagine herding a toddler in what I wore 10 years ago. I'm grateful to qualifyfor the "mom" uniform.