https://www.mangago.zone/read-manga/my_wife_whom_i_loved_dearly/
(Fuck cancer)
https://www.mangago.zone/read-manga/asagao_wa_yoru_kara_saku/
(Fuck my life)
https://www.mangago.zone/read-manga/hundred_ghost_stories_of_my_own_death/
(Not really a sad story more like horror but sometimes the story can be really sad too)
I think banana fish and haruka tooki ie kinda hurt too
Have you tried this?
https://www.mangago.zone/read-manga/december_rain/
https://www.mangago.zone/read-manga/baraou_no_souretsu/ (depressed is an understatement as to how this manga left me. Its beautiful btw)
https://www.mangago.zone/read-manga/shuumatsu_no_laughter/

Any reco that will leave a hole in my heart- omniscient readers viewpoint, 10 years I love you most, gaze at the scene of debauchery type sht