In a general sense, when we read the word "apocalypse" we think of cataclysmic, end-times destruction and ruin, synonymous with "armageddon."  But Bakker knows words and etymologies.  "Apocalypse" really means "uncover" or "reveal."  Our association of the word with destruction comes from the Revelation (Apocalypse) of John being largely about the destruction of the current world.

Bakker could have called the series the Second Armageddon if he wanted.  "Armageddon" gets across the same idea, and actually comes from the name of a Biblical battle plain where there was/will be lots of death.  In fact, Bakker maybe even primed himself to be able to use the word by including a very similarly named and functional "Mengedda" in Earwa.
So back to "Apocalypse," the first one.  Unveiling of the No-God?  Then of course it happens again the second time around.

BUT (and now I dive deeply into an obscure word choice that Bakker almost certainly meant nothing by)

Why is Umiaki (the tree of the Circumfix) a eucalyptus?  The Three Seas are pretty clearly analogous to the Mediterranean and the Middle-East.  There are plenty of trees he could have used that are associated with the area (cedar, sycomore, acacia), but eucalyptus, I'm pretty sure, is only native to Australia (maybe also New Zealand and some islands around).  So why eucalyptus, it seems jarring and out of place.  That's right, it shares a root with "apocalypse."  Almost the opposite really, "eu" meaning "true" or "actual."  So Umiaki is the actual covering, the actual hiding.  Hiding what?  Not the No-God, he sleeps.  The hiding of Ajokli in Kellhus of course.

If there is any merit to my leaps, then the importance of the Second Apocalypse is maybe not the uncovering of the No-God (not that it isn't a huge deal), but rather un-hiding of Ajokli from Kellhus and his freedom from the Outside (since the No-God has locked him out so to speak).

Thoughts?

In WP chapter 21, the synthese is flying over the sack of Caraskand.  "And though Golgotterath had long scoffed at the Mandate and their prattle regarding the Celmomian Prophesy, how could they afford to take chances?  They were so near! So close! Soon the Children would gather, and they would rain ruin upon this despicable world! The End of Ends was coming..."

This does not sound like a plan to resurrect the No-God, knowing how the No-God is eventually resurrected.  And considering that they used an Anasurimbor the first time, shouldn't the Consult be pretty clear on what Kellhus showing up means?

Reading it this time around, this part almost sounds like the Inchoroi gave up on the No-God to seal the world plan, and have called on Inchoroi from the depths of space to come and blast the world away.