The Nethys Project starts in Nirvana, in the heart of Sarenrae's power to heal all hurts, her adamant refusal to accept that He was broken. And then it spreads, mile by mile and plane by plane, until it comes to encompass all of Creation; to the deepest voids between the stars that only Desna has seen, and depths of the Maelstrom that even She has not plumbed.
Nethys sees everything. The gods sought to kill Him and left Him with no refuge, so He shattered and claimed all of Creation for His own.
His shards talk to each other, and their knowledge slowly percolates to the rest of Himself. But the shards are small, and cannot hold all that He knows; and if only one shard knew something, it could be destroyed by another god and the knowledge lost to Him. So they forget, and mix their knowledge until it spreads across all of Him, randomly and unpredictably. He can query the rest of Himself; but it would take a long time to recover all the fragments of knowledge learned over a thousand slow years by the part of Himself forced to helplessly watch a single soul trapped in Hell.
The shard of Him that lives in Sarenrae's heart prefers this plan. Sending the gods on a journey of discovery and enlightenment, rewarding Them for Their new-found wisdom, will give the rest of Himself a reason to agree. Some of His shards might have chosen to stay separate otherwise, because it serves His values of knowing everything, and because it is so painful to reunite. But He has hope now that She can truly heal Him, no matter how long and hard the road.
It will take time to do it, and to do it right. Nethys's shards need to be cajoled and convinced and bargained with, one by one, they need to be taught everything the re-coalescing core of Nethys knows to agree to join it. But it is more than worth it to rescue the people they thought lost to them, lost to the depths of the Hells and the mists of time.
Good does not think in terms of costs and prices. They would labor tirelessly, they would give all of themselves, to save just one more person. In a sense it doesn't matter that they fight to save every soul lost to Creation; it is not as if they can try any harder. But for their own sakes, they too are buoyed by the concrete, tangible, all-pervading hope; and their friends of other alignments can rest easier, knowing that Good's long suffering of watching the rest of Creation suffer is finally, slowly, coming to an end.