The Side Character Wants The Spotlight

Gabriella considered herself as a side character even in her own life who always gets compared to the Main Character, her best friend. She died after wishing for her Best Friend and its lover to have a happily every after, but returns back in time instead. Does that mean her best friend won't have the happily ever after she wished for? What will Gabriella ever do? Is stealing the spotlight from the Main Character the only way for her wish to come true in her second life? What if... it's not?