thats literally every childhood to lovers bl dude, since its a manga u cant even tell their hair color or shit lmao good luck
i'm pretty sure it's not this BWHAHAAHAH, but it has similar backstory, u might wanna check this out
https://www.mangago.me/read-manga/someone_else_s_bl_manhwa/
WAIT, SORRY WRONG STORY!
Tomorrow We Won't Be Friends For Sure, Right?
https://www.mangago.me/read-manga/ashita_wa_kitto_tomodachi_janai_yone/
it's like innocent love story, they always study together I think? or just hang out at the ml's house something like that
how innocent? any other details?
here’s some, idk if they’re it:
https://www.mangago.me/read-manga/kagakubu_no_megane/
https://www.mangago.me/read-manga/18_44/
https://www.mangago.me/read-manga/nagahama_to_be_or_not_to_be/
this one isn’t innocent per se but it fits ur criteria for childhood neighbors:
https://www.mangago.me/read-manga/kimi_no_tabegoro/
it's a bl manga, I think they are childhood friends? or maybe neighbors I quite don't know anymore but they were bestfriend and also classmate. They went to ml's house and like and they kissed and then that, I don't remember anymore fawk