lol help a girl out.

There’s this bl I read I don’t remember the title but the story goes something of the bottom is like a substitute for the male lead’s first love or whatever but this story the substitute is like in a world of novels acting as the substitute and making the male lead fall in love with the substitute instead of their actual love in the story. It’s like a system set up where he like saves the substitute’s tragic lives in that story but as a system? He has a little robot as his assistant. I remember I think the first world he was in he was a substitute for the first love who was like blonde or something but the blondie only cared about himself and the male lead slowly started to realise only the substitute loved him and cared for him the story goes on and it comes to an end where the substitute finally succeeded in his mission and he exits the world so dramatic by having some bone cancer or something and then into the world he goes. ╮(￣▽￣)╭