Is it this?
https://www.mangago.me/read-manga/the_horizon/
No.
Was it on Webtoon Canvas?
Not sure, I read it on Mangago
I'm not sure what it is but here are two other titles that sorta match
https://www.mangago.me/read-manga/about_death/
https://www.mangago.me/read-manga/annarasumanara/
If neither of these are it can u tell me what else u remember?
Its neither of those, I think there was something about MC's potential brother/sister that wasn't born (?) and there were grim reapers that were obsessed with MC (?) that maybe tried to bring him back to life or something (?). I didn't include any of these details because I'm really not sure about them
Is it one of these? If not, I don't know if I can find the title you're looking for :(
https://www.mangago.me/read-manga/gepetto/
https://www.mangago.me/read-manga/ghost_teller/
Neither of those :')
Sorry, I'm out of ideas... (T_T)
Old webtoon, MC is a child that died and ended up in an orphanage full of other kids and the surroundings are pure white. he ended up escaping into that white with another kid and they adventured and found a school with a kid stuck there. They roleplayed being students and relieved the kid of trauma or something. Then they went to a carnival area where there was drama between a brother and sister. And then where I last remember was a city full of fake people except 1 kid