You've got your facts a little bit wrong. While the Borg cube featured in "Before Dishonor" was in the AQ before "Endgame", the Borg fleet in "Destiny" attacks because of the events of "Endgame".
... yes, that's what I said. The Borg cube in Before Dishonor
-- called the "supercube" because of its advanced assimilation technology -- was in the Alpha Quadrant before "Endgame" and was cut off from the rest of the Collective. It attacked the Sol system and was defeated. Then, separately and coincidentally, the main Collective's fleet began attacking Federation and other nearby targets after discovering a subspace conduit capable of bringing them to the tri-border from the Delta Quadrant.
Either way, the supercube's actions in TNG: Resistance
and TNG: Before Dishonor
were not in retaliation for the "Endgame" attack.
That being said, it's also said in "Racing the Clock" (may have the title wrong) that in pretty much every timeline where the events of "Endgame" didn't occur, meaning the Caeliar don't run into the Borg at the space and time when they do, the Borg essentially end up overrunning the Milky Way.
Yep. Though the novel was Department of Temporal Investigations: Watching the Clock