What Did I Get Wrong on the Road to Redeeming the Villain?

If you get another chance, can you really get the ending you want? A girl prays to the gods, pays the price, and receives a miracle, all to save someone's life... But did something go wrong in the end? She only wanted to stop that girl from becoming a villain, so how did she end up becoming the mastermind Big Boss herself?! (A little angst, revenge, maybe some sweetness. A refined and easygoing series. Please read civilly.)