I have a theory that "Children of Time" (DS9) and "Before and After" (VOY) were the same timeline.
Both timelines were rewound back to the same year, 2373. That's also just one year before "Year of Hell," where we learn Annorax is constantly changing history. So the fact that in the same year, both Kes and Gaia-Odo both made decisions that altered the flow of time, may not be a coincidence.
If indeed they were both one timeline, it's a pretty bad one. Sisko and the entire senior staff of DS9 vanish right before the Dominion War; meanwhile, Janeway dies right before the infamous alliance with the Borg. So in the Alpha Quadrant, the Dominion probably wins the war and conquers or destroys the Federation. Over in the Delta Quadrant, the war between the Borg and 8472 rages on. B'Elanna Torres is also dead, so that Klingon ship never gets their messiah. And Seven of Nine is still a drone.
The galaxy is pretty frakked.
But what are the odds of the entire staff of DS9 being on the same craft for a routine mission, and falling into a time-wibbly, right before the war? What were the odds of Janeway and B'Elanna both dying from a frigging exploding consol at the same time, right before freeing Seven of Nine and defeating 8472?
I think this was all somehow the result of Annorax's time meddling. It got Janeway and the Federation out of his way. He likely undid this timeline because it caused the Dominion, Borg, 8472 or some combination of the three to annihilate the Krenim.