Anyone knows some manga that are similar with Shimanami Tasogare and Ao no Flag?

i heard that faded first love is similar

http://www.mangago.zone/read-manga/smells_like_green_spirit/
Also deals with bittersweet feelings and coming to terms with sexuality in a high school setting

I'd also recommend My Brother's Husband if you liked Shimanami Tasogare since it's also a meditation on being gay in Japan that hits you in the feels: http://www.mangago.zone/read-manga/otouto_no_otto/ (no romance or sex)