Recs

you asking for "rainbow city"?????? YES YOU ARE ε=ε=(ノ≧∇≦)ノ RAINBOW CITY! RAINBOW CITY! (SA in chap 3, best to skip)

Manhwas
https://www.mangago.zone/read-manga/cocoon_of_the_heart/
https://www.mangago.zone/read-manga/dangerous_convenience_store/

Mangas
https://www.mangago.zone/read-manga/kitto_oujisama_ga_nante/
https://www.mangago.zone/read-manga/nirameba_koi/

https://www.mangago.zone/read-manga/sangyang_the_wanderer/
https://www.mangago.zone/read-manga/murderer_llewellyn_s_enchanting_dinner_invitation/ can’t pick between these two

try this one!! its my current fav ^_^
https://www.mangago.zone/read-manga/spinach_bouquet/

https://www.mangago.zone/read-manga/here_u_are/
This is always gonna be my favorite BL