Heart Stain
https://www.mangago.zone/read-manga/faded_first_love/
This one should fit the bill! Features both sweet romantic relationships and friendships!
https://www.mangago.zone/read-manga/tractor_full_of_love/
https://www.mangago.zone/read-manga/spreading_you_out/
https://www.mangago.zone/read-manga/kore_ga_saigo_no_koi_no_hanashi/
https://www.mangago.zone/read-manga/given/
https://www.mangago.zone/read-manga/the_man_who_can_t_taste/
https://www.mangago.zone/read-manga/sketch_1/
https://www.mangago.zone/read-manga/ways_of_parting/
https://www.mangago.zone/read-manga/bongchon_bride/
https://www.mangago.zone/read-manga/eiffel_tower_at_sunset/
koi ni mo naranai
Wait I just realized you specified Korean BL’s whoops!
Cute shounen-ai where character A is into character B but along the line he falls for character C like Heesu in class 2, For Your love and Bad Contact.
(NOT like Lost in The Clouds, I want FLUFFY and healthy and cuteness)