The manhwa you listed are all by Korean authors I believe, you may have some luck with Japanese authors, even female ones who can write without fetishizing the gay experience. Try checking out:
Saezuru Tori wa Habatakanai (Twittering Birds Never Fly)
Blue Sky Complex
Rumspringa no Joukei
Dear Gene
Yoichi to Tsugumo
anything by Higashi Nishida (a ......
