These sort of fit what you're looking for:
https://www.mangago.zone/read-manga/kill_me_now/
https://www.mangago.zone/read-manga/other_than_my_friend_s_sister_something_else/
https://www.mangago.zone/read-manga/himawari_san_sugano_manami/
https://www.mangago.zone/read-manga/takane_no_hana_wa_usotsuki_desu/
https://www.mangago.zone/read-manga/ane_no_yujin/
These definitely fit what you're looking for:
https://www.mangago.zone/read-manga/does_it_count_if_your_first_time_is_with_an_android/ (side character is in love with the MC since she was a kid, nothing ever happened between them though)
https://www.mangago.zone/read-manga/serenade_keum_kyesoo/ (side character is in love with the FL since she was a kid;toxic relationship between the FL and side character, non-con between the FL and side character)
https://www.mangago.zone/read-manga/this_love_that_won_t_reach/ (age gap, MC is in love with her sister-in-law; rushed and ambiguous ending)
https://www.mangago.zone/read-manga/immoral_parody/ (short story;non/dub-con, toxic relationship)
https://www.mangago.zone/read-manga/the_nest_of_eternity/ (short story;toxic relationship, non-con)
OMFG THANKYOU
GL young x older and have known eo since the younger top was a kid and the younger top always has a crush on her since she were a kid.
so um when she became adult and her feelings only grew and confessed to older bottom doesn't take it seriously and only disregard it the next hour haha do you guys have something like that? i rarely read gl and never have i encounter a younger top x older bottom who knows each other since as kid/teenage.
maybe um similar to Lover Boy and A Tree Without Root's characters? ╥﹏╥