Arthur/Morgana this can't be how the story ends (ouat!time travel au)

AU, inspired by the season 3 finale of Once Upon a Time -- Arthur doesn't die after the Battle of Camlann. Instead, he lives and feels the guilt over Morgana's death. When a new big bad opens a time travel portal, Arthur gets sucked in-- still thinking about how he could've saved Morgana. He ends up in s2 era, and after the initial shock, he realizes that he can use this opportunity to fix things with Morgana and maybe help his past!self get on the right track this time. (I haven't vidded in