Some among the Neutral gods abstain from the war, though even most of those do lend Their efforts to monitoring the qlippoth, or standing by if Otolmens at Rovagug's vault should call out for aid.
Gozreh abstains wholly, as do some other gods, but not many.
In truth, for Creation to embark upon a wealthier Future benefits many gods, if their concerns are manifest in mortals at all. If you like mortals existing in the first place, you probably like Creation being ten times as full of souls.
You would think it would benefit even Pharasma, to have more souls to sort; or that it'd benefit Pharasma to receive fewer souls dying before they show an alignment, to have less of a torrent of dead babies come to the Boneyard; you would think She'd have done something earlier to promote technological progress, even if just to back Abadar or unleash Axis's investors. But Pharasma is as inscrutable in Her own way as Rovagug: mostly She judges souls, and the exceptions She makes to that behavior pattern are not for mortals or even most gods to predict.
But this great Change to the equilibrium She previously set in motion, Pharasma does not act to oppose; for Keltham has a death-grip about Her Spire, and it seems that can inspire Her at least to inaction.