Happy shitty life by harada and Neko x Neko. But rly there's like 5 mangas with switch couples and I wish there were more
http://www.mangago.zone/tag/seke/
(there are both manhwas and mangas here btw)
theres inner beauty
blue hair guy(oops i only know yuri's name) from yarichin bitch club is a switch
http://www.mangago.zone/read-manga/neko_x_neko/
not a manga or a manhwa(it's western) but this - https://yaoi.biz/avialae/chapter-1/page-0
it's also available to read on tapas, but it's censored on there :)
Can you recomend me some yaoi manhwa were the copule is switch? I've read so many yaoi manhwas but there always was top and bottom only