Phoebe wanted to resurrect her mother and make those hypocritical gods, who were all talk and no action, pay for their pretentiousness.
Thus, Phoebe drastically altered her plan, becoming even more aggressive. She didn't hesitate to abandon her carefully chosen apostles, personally transferring power to John, helping him grow stronger.
In secret, Phoebe continued to gather information about her mother, attempting to bring her back to life. Phoebe succeeded, but not completely. Over the years, she managed to recover most of Seraphina's soul and power, but the most crucial fragment of Seraphina's soul remained on Mount Olympus, guarded by Zeus to prevent Seraphina from ever returning.