Super Soldier serum seems to get rid of body hair (bc Erskine's ideal man is a baby smooth twink?) as seen in the progression of Bucky's chest hair.

Tony has always manscaped. His pubes are the same shape as his beard goatee thing

Matt has so many possibilities. I figure electric clippers makes the most sense since they're fast and his perma-stubble seems like it's from the length guards that prevent him shaving off his nips/nose/whatever.
Or for the waxing route There might be an office spa day where he paints Foggy and Karen's nails, Foggy helps him wax, and Karen rubs that blue soothing stuff on him while Foggy braids her hair

Tl;dr: Matt and Steve are probably fine. Tony is fucked