Unfortunately, it is very uncommon to find oversized who don't have small skinny waists and arms, and almost every male chatacter is either scrawny or extremely muscular. These are the only ones I know :(
(def check this one)
https://www.mangago.me/read-manga/red_dot/
https://www.mangago.me/read-manga/suimitsutou_ha_shoujo_ni_kajirareru/
Also I recommend reading heartstopper. While I wouldn't consider the characters oversized the author tries to depict different body types and the story overall is great.
Romance mangas or manhwas with oversize characters? Preferably bls. Thankssss.