did you say you want "rainbow city"? yes you did (SA in chap 3, best to skip)
these are all the post-apocalyptic bls i can think of rn:
https://www.mangago.zone/read-manga/undead_tsuyuhisa_fumi/
https://www.mangago.zone/read-manga/uruwashiki_shuen/
https://www.mangago.zone/read-manga/a_dead_crow_s_stare/
https://www.mangago.zone/read-manga/believe_my_sign/
https://www.mangago.zone/read-manga/epitaph_perfume/
God I just finished reading rainbow city and I think it's one of the most interesting post apocalyptic bls I've ever read and the romance is so perfect im obsessed with it
IKRRRRR AOVJOA;FBNP'DHI;GRAEGRH'GOROGPIGPDHOIIHHO YOU GETS IT AEEEEEEEEEEEEE IM SO HAPPY AFUFEVHUAJBAKJBJBAITS SO TRUE GRRRRRRRRRR
dystopian, post–apocalyptic bl recos pleasee, something similar to “a room without window”