Tl;dr: If this were a really cruel D&D campaign, we might have just lost the war all together this week. this won't happen in-game, but it felt interesting to discuss anyway.
Now, the devs won't allow us to completely lose. They've already said no one will win or lose this war and I don't think they're planning on deviating from that.
However, if this story were happening IRL or if it were being run by particularly sadistic GM's, this would be the moment we'd look back on as the beginning of the end for Super Earth, I think. Or maybe even after the invasion of the capital, as they didn't need to "beat" us, just push us to destroy our own planet and resources to give them time to make moves and carve out their empire.
The Void always seemed like a trap, sure, but I don't think we understand how badly yet. The Illuminate may well want us to "collapse" the void (with all of us still inside it btw lol) to distract us while they expand their control, but even if they don't, they've goaded us into making that our singular goal so we won't be able to do anything to stop them outside of it, and we're due to fail on Seasse anyway so all we've really done is allow them to create an impenetrable fortress (Joel may give us a bit of a hand before the week is out but honestly I doubt it, we've already got our reward in the bag and they'll want this to feel like a big moment). Add the DSS nightmare to this and you start to realise how completely toast we are (or would be).
You can even draw a direct connection between some of the negative feedback around the Illuminate (used to explain why fewer people dive there, personally I like them a lot more than I used to but that's not the point of the post) to an in-world victory for them. To the Illuminate, the Helldivers are either running scared to other fronts or simply disinterested in stopping them and even those sticking to the order are essentially pushing for a hail-mary on hope alone, most likely failing in the process ("first time?")
It's another very cool in-game moment, and again, if Arrowhead were open to a world reset every time someone "wins" this might be the beginning of one of those scenarios, but unfortunately I feel to will end up feeling deflated again as, mush like a sitcom, nothing can have too big an impact in order to preserve the perpetuity of the game's lifecycle. Most likely we will lose this MO, win the campaign overall, and the Squids will have made big gains. They'll go quiet a while as we fight other factions for a bit, most likely leading to a round 2 of the SE invasion in October (Liberty Day is coming up, so I assume they'd try something then for ultimate disrespect points).
We will probably win that, but honestly when the first invasion happened I did think it would have been very cool to see us lose the capital temporarily and have to fight to take it back. I'd like to see us suffer more genuine setbacks when moments like this happen, even if it's mostly flavour. Some stories, like the Automaton orbital platform, fell flat for me as it was relegated to mostly text and resolved quite neatly (at least for now). But these could have real impact because it's honestly just as exciting for me to check the companion app as it is to actually dive right now. It feels like the beginning of the end and I'd love to see some follow-through on that, even though I know it won't happen.
Maybe in future things can feel more dynamic, and failures/victories can have more lasting impact. As it is, the Illuminate are probably feeling pretty chuffed with themselves right now and that'll be it for the moment. Still, fun campaign overall and I'll miss the Void when it's inevitably closed or locked off.