Do away with time travel. The crew stumble across an old transwarp hub, one damaged in a plasma storm and since abandoned by the Borg. The crew find that they could be able to repair it and use it to get home, though also realise they could deal a significant blow to the Collective it they used it to sabotage the network, they also face the highly likely probability that when they reactive it they'll open up that region of the DQ to a new Borg onslaught. Janeway is faced with yet another impossible decision, similar to that which started them in the DQ.
The crew decide to attempt and use the hub to get home as well as carry out sabotage, however to do both someone must remain behind to initiate the computer virus that will cripple the network. Janeway takes it upon herself to be that person (as she has done in the past). As the hub repairs are completed an energy surge activates it prematurely, signifying to the Collective that it is operational again. A Sphere is sent to investigate and emerges. Voyager raises its shields to defend against the Sphere, stranding a team (most likely including Seven) on the hub. As the ship takes a beating, Seven manages to beam the other back to the ship and insists they use the hub to escape, she will carry out the sabotage.
With no other options and only a couple of hits away from destruction, Janeway orders the ship into the hub, heading for the Alpha Quadrant. It could essentially end there, with Seven doing the most human thing possible and sacrificing herself for her family, or if there has to be a happy ending for all then a Wedge crewed by the freed Borg from Unimatrix Zero shows up just as she is about to press the button and takes on the Sphere. One of the liberated drones takes her place, whilst she is beamed aboard and taken into the hub after Voyager and emerges in the AQ to be reunited with them.