I'm around, just busy-busy-bee
I've just not been sure about this one; backdoor hacker is supposed to be pretty lethal But yea, an arty golem pulling a Kool-Aid-Man directly onto your homeworld is a bit much.
I don't know if it would work, but what about setting a max ship size that can come though the Exogate on the human homeworld? Most Golems, Hunter killers and Motherships would basically be game over unless you had an insane amount of fire power waiting for them. So basically if the AI decides to send a wave right into your home system, you see a ton of little ships and group of starships, but nothing that is bigger then a Starship. That should leave the difficult of it there, as you have waves of pain at any potential time, but those waves can't basically just have you lose if you have decent defense set up.
Also set a minuium range that it can be from the Home station, so you have time to destroy stuff before it can start shooting at you. There is a big difference between a gate/wormhole at 2000 and 20000 units when the AI comes knocking though it. Not that I have found a way to see how close they are in the game without using ships, but some of them are so close I think that people on the other side of the wormhole should be able to shoot them though it.
The issue is more of a hard, not impossible to beat. Fallen Spire should not become no longer an option just because you got the Backdoor hacker and you find Golem that instantly(or just about) kill your Home Station even with every FF in existence on it coming in one of the EXO waves.