Responses
Oop nvm. I found it. Good thing it was not really far off from my already read list i did a quick skim and boy was i so wrong about my description it's been more than 5 years since i last read it so some details were wrong. Anyway, for those who were curious, this is the link:
https://www.mangago.zone/read-manga/back_in_time_to_you/
So i read this a few years ago and it's short (like 3-10 chapters) + completed. It's a bl that is tragic about mc finding a telephone that connects to someone from a different timeline. I'm also pretty sure that the ml is an artist? I forgot what happened but i do remember that the place mc currently lives in is also the same space where ml lives, but they can't see each other because of the different timeline. They can only talk through a telephone. Also, mc described what he looks like to the ml (?) And the ml drew him? Years later, the mc found the ml's sketchbook and saw his face. Ml is dead now btw. Also, i think one of them has long hair.
My description is very vague but if someone do find it, I'm very grateful!