Straight
https://www.mangago.me/read-manga/90_s_cram_school_for_unripe_apples/
BL
https://www.mangago.me/read-manga/internet_love/
https://www.mangago.me/read-manga/tamaranai_no_wa_koi_na_no_ka/
https://www.mangago.me/read-manga/boy_meets_maria/
https://www.mangago.me/read-manga/cherry_magic_thirty_years_of_virginity_can_make_you_a_wizard/
https://www.mangago.me/read-manga/hidamari_ga_kikoeru/
https://www.mangago.me/read-manga/spinach_bouquet/
https://www.mangago.me/read-manga/minority_1/
https://www.mangago.me/read-manga/cupid_ni_rakurai/
I feel like they have the same vibe as kieta hatsukoi xp although some have themes of angst and personal growth beetwen the romance. I hope that doesn't bother you if you were just looking for a colorful fluff

please please pleaseee recommend me stories like
https://www.mangago.me/read-manga/faded_first_love/
doesn't matter if it's bl, gl or straight, thank you in advance