ready_player_1

the horizons rlly good, you can talk about how in a sense war automatically justifies death and also the different perceptions of lawful deeds, when theres no law to follow.. (its pretty short but theyre are alot of concepts- greed, survival, aggression, mortality, etc.)
https://www.mangago.zone/read-manga/the_horizon/

I know a novel though.
http://wbnv.in/a/84gBR4z

This novel's quite similar. Maybe....

https://www.mangago.zone/read-manga/no_6/
No 6 is a perfect district as long as you declare loyalty. Outside the wall is the "outsiders".

https://www.mangago.zone/read-manga/20th_century_boys/
A classic. A man found out his childhood dream is slowly becoming reality. Except that it's not a "good dream"

https://www.mangago.zone/read-manga/yokohama_kaidashi_kikou/
Humans slowly become extinct, story taken from an android's POV.

https://www.mangago.zone/read-manga/litchi_hikari_club/
It's gory but left an impact. Bunch of high school students tried to build a "perfect robot"

http://www.mangago.zone/read-manga/watashitachi_no_shiawase_na_jikan/

Nevermind, I reread your post. My recommendation is not bl. It will still leave you in tears, but not bl.

Does it have to be a manga/ webtoon, or do you also read novels?

http://www.mangago.zone/read-manga/10_years_where_i_loved_you_the_most/
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http://www.mangago.zone/read-manga/i_will_be_waiting_for_you_in_1999/

this one was a different type of hurt, idek man. it wasnt even THAT sad but gosh i cried like a bitch xD
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http://www.mangago.zone/read-manga/mahoroba_no_hibi/
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http://www.mangago.zone/read-manga/lonely_to_organdy/

this one also hurt like hell
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well you did ask for sad bl recs so im hoping they are to your taste. maybe im just emotional but i cried reading all of these. enjoy! (づ￣ ³￣)づ

Have fun (๑•ㅂ•)و✧
http://www.mangago.zone/read-manga/banana_fish/