your description reminded me of 2 manga, but neither of them fits the whole description, either way a good read:
https://www.mangago.zone/read-manga/tokyo_crazy_paradise/
https://www.mangago.zone/read-manga/keishichou_tokuhanka_007/
you can try going through the Yakuza tag, it has only about 350 pages ;)
https://www.mangago.zone/tag/Yakuza/
or you can try using the Baka Updates advanced search, there you can search the genre and tags at the same time
https://www.mangaupdates.com/series/advanced-search
Indeed It's neither of the above you mentioned but thanks for the suggestions! I did try searching with the Yakuza tag here but there were far too many manga that I got tired ㅠㅠ I will give the baka updates a try! Thanks!
I am looking for a 90s style drawn shoujo/josei Yakuza manga! I read it years ago and I can't seem to find it on my list anymore... The manga opened with the ML getting stabbed from the enemy gang and the GL finding him on the street and treating him and hiding him until he is better! After that they go through many ups and down in their relationship, she even gets kidnapped and almost hurt by the enemy gang whose leader has also taken a liking to her (or more accuratelly wants to torment ML using her) before ML saves her...She had long fluffy blond hair in the cover while ML had dark hair!! I also remember the ending which was their wedding and the ML dying after getting shot after they end the ceremony and dying leaving her alone in the end (which left quite a big impression on me...)