Responses
Ok ik this isnt exactly what you asked for because it has a teeny bit romance but thats only in the flash back and nothing present plus the story is peak so try Hell's paradise (jigokuraku)
if survival means charas living in precarious worlds:
https://www.mangago.me/read-manga/ark_of_the_law/
https://www.mangago.me/read-manga/the_end_of_the_world_is_just_a_game_to_me/
https://www.mangago.me/read-manga/night_of_shadows/
https://www.mangago.me/read-manga/dorohedoro/
https://www.mangago.me/read-manga/fool_s_night/
Pls.