https://www.mangago.me/read-manga/rainbow_in_the_sunset_glow/
Ngl this one is conflicting in im not sure if it's romantic story or could also just be closeness between family but if it is it's kinda uncle×nephew so uhh be aware. Also is a oneshot ( if u like this i recommend checking the author other works same for the story below)
https://www.mangago.me/read-manga/the_hands_the_demon_adored/
Sad/bittersweet as well a one shot
https://www.mangago.me/read-manga/run_away_with_me_girl/
Sad but does if I remember correctly a happy ending
https://www.mangago.me/read-manga/july_found_by_chance/
This one i personally think is a bittersweet story
Here is my list dear, I hope you enjoy
https://www.mangago.me/home/mangalist/1750995/
Need recommendations sad story/angst plot
I don't mind if bl or gl or romance or whatever but sad plot pls pls