I'd argue a Moira in each or even just many of the parallel realities constantly burning and resetting each reality actually would qualify as catastrophic, particularly for beings that exist outside them and move between them. Your own theory rests somewhat on there just being one Moira in the multiverse and it only happening in 616 but we've no indication that's the case and more it seems pretty unlikely. I mean we know there were Moiras in Rachel and Bishop's realities and those are just among the X-Men, provided Franklin recreated them. As soon as we see any alternate post-SW Moira things get complicated quickly.
I'm actually getting tired of the conversation, and you're really struggling here.
1.) No one is "constantly burning and resetting each reality." Moira is just resetting the timeline. If you read any of the other marvel books this happens *constantly*. The Abstracts don't show up every time someone uses Doom's time machine for something dumb.
2.) There is exactly one Moira in the universe that we know of with this particular powerset. It's entirely unique in the history of the X-franchise and we've never seen anything like it. There is no reason to assume there are millions of her since once again the universes Franklin created are unique. The point was to explore the universe and make unique creations from his imagination, *not* a billion copies of the same universe with slight changes. And for the last time- much of what Franklin made was destroyed by the Entropy abstract. Universe-8 is very, very small right now compared to Universe 7. Small as in "nearly wiped out entirely" and Franklin is unable to make any more universes to save what was lost. This is causing him severe distress in FF right now and is a major plot point.
3.) for the last time- Rachel and Bishops futures are not alternate universes. Marvel has retconned them to alternate *futures*. Those futures all take place in the exact same universe exactly as Cable's does. We know for certain this is the case because Ahab showed up in extermination to reclaim Rachel as a hound from the future of 616, and Bishop comments on his mission in Astonishing vol. 2. Ahab continues to talk about this in the post extermination "Cable" series. He's from the future, not an alternate universe. These people are not from "alternate realities." They are from Earth 616 decades in the future, though those futures may no longer be valid. *alternate universes due to time travel have been impossible since AoU and Marvel has retconned them out*
4.) The librarian states flat out that if the Dominion discovered what Moira was, it would consider her existence intolerable and do something about her. You're wrong about Moira VI, she had no idea post human acension was even a thing- she was stuck in a zoo with every other mutant with no knowledge of what was happening.
It seems a discussion with you isn't that productive since you're struggling with the material, so I'm disengaging.