Someone reborn as Sung jin woo's twin brother or older brother, depends on what you want, So my idea is the MC will be reborn as Sung jin woo's twin brother or older brother and then be awaken as a Hunter that has space ability, then he will make his own hunter agencies, etc.
So when the canon started, make some excuses so Sung jin woo will still go to the double dungeon with the MC, with the plot still there so when everybody is getting out of the dungeon, MC will stay with Sung, with excuses like not gonna leave his brother, then when they wake up they both will have the system, after that when the time for the job selection the MC will utilize his space ability and defeats everything after that he'll get the Space Monarch/ Cosmic Monarch (I don't know anything good that has space in it, so I just went along with it)
Of course when he gets stronger he can go to another anime world, then all you have to do is create some enemies like world eater, overlords, something. (So that's basically what I thought, Honestly I just write whatever that pops out of my empty brain, that sounds good in here.)