okay, so finished my rewatch and i think i have a general idea for post-canon jinwoo. obviously it's implied that he's in the instance dungeon the way sejoo was. and while sejoo can't check because the game is reset i think that once he establishes his own company and starts doing his research he'd be able to figure out how to get jinwoo out of the dungeon without the quest. obviously it would take at minimum a year to even figure it out and maybe another year to put it into action.
but sejoo made the game, he made the instance dungeon, so he could figure out a way to get jinwoo out. i think once he does, jinwoo would very much live a quiet life. not so much like go off the grid or anything. but more like keep himself out of the public eye. but also i could see him working for sejoo's new company. maybe not offically, but helping him with research and giving his insight from when he was playing the game because it would be helpful since jinwoo is the highest leveled player as well as current master and played the game the longest other than sejoo and marco.
also i don't think he'd step away from the game either, not completely. i like the idea of him being a sort of "hidden ally" in the game that appears to help players when they're in critical danger the way the glitch was with junghoon. but also, maybe instead of him actually being in the game or playing himself he could have sejoo design an npc of his user to add to the game.
but i could see him still logging on once in a while because it's a habit he can't break but he wouldn't try to fight or duel or anything like that. i think it would bring him a sense of comfort and relief to see the game as it was originally supposed to be and that through his years of suffering he was able to help bring it all to fruition.