Why don't you count those two as Borg books?
Without giving away much. As HappyDayRiot
said it is the first two Voyager books set after their return to the Alpha Quadrant and is more about them coming home and coping with that. However even the part of it that involves Borg technology and that threat is not
The Borg (from the Delta Quadrant, that has been a threat to SF for many years). It is a misguided Admiral in Starfleet who is trying to use that technology for very
I liked Resistance and Before Dishonour. The former being a borg attack and the latter being the reprecussions from it. And then Greater Than The Sum being the reprecussions from the reprecussions.
WHAT?!?!? Before Dishonor was far from just being the repercussions of the previous book. And it in fact did have quite a large Borg attack of its own. Larger, IMO, than any other Borg attack we've seen to date.