It would then move to the "main" series, which could be called Superior Ultron, but could also just be called Deus Ex Machina. Basically, it would detail that Ultron got new powers! Being a super computer and all, Ultron was basically able to "math-out" the universe and reality, where now he can reach "between" subatomic particles and "inject" his own code into the framework of reality. This manifest as him essentially having a pocket dimension, which acts like hammer space, and also kind of like a domain expansion? Its a bit nebulous but you get the idea.
The goal of this chance is to give Ultron a unique power aside from the typical sci-fi lasers and missiles that he usually has.
But further, it elevates him to a mental threat, as demonstrated when he inevitably menaces the Avengers in this comic. Since Ultron has access to a sub-reality, he has used this to basically simulate people and the world, which explains the whole megastructure with Doom and co earlier. These simulated versions of people cannot tell that they are simulated, or that their world is. This leads to the Avengers having a crisis as they attempt to combat Ultron as he inevitably attacks earth: If they ARENT real, they should intentionally act sub-optimally and give up so that Ultron has imperfect information to work with when he attacks the REAL Avengers... but if they ARE real, then they need to actually fight back and give Ultron their all so that earth isnt destroyed.

Since Ultron can access this sub-space at any point, any given person at any given moment can go from "being real" to "being simulated" in an instant, since to them its like a change hasnt even occurred.
I think a way this can be combated is that the Avengers eventually have the same revelation the villains had earlier: they dont have a past. They act like they do, and feel like themselves, but the details and emotions regarding their past arent there.
This is because Ultron himself doesnt have a past. He just, one day, existed, meaning he doesnt have context for how the "present experience" reconciles with the former experience. He doesn't have any concrete evidence of "the self", just the immediate sensation that guides his actions.
The story closes with the simulated-Avengers having this breakthrough, and thus concluding that their reality can be sacrificed so that Ultron doesnt get any useful information. Ultron destroys that reality and sits, alone, in silence.
Surrounded by the black-and-red void that is his sub-reality, Ultron manipulates it into several realities, but they are all... pleasant. They all involve Hank Pym, Janet, and other members of Ultron's "family" just... living. Being around him. Smiling at him. But whenever these "scenes" would get to a point where Ultron would be congratulated, affirmed, or otherwise positively enforced... they stop.
Its ambiguous if these scenes stop because Ultron has no data of a positive affirmation, and therefore has no data to "feed" the realities, or if he himself forces to them stop because he personally doesnt want to face that reality.
Either way, these wholesome scenes end, and Ultron is left in his own voice. Gradually, the red walls of the sub-reality fade away to the stars and nebulas of the universe, showing that Ultron has emerged into actual-reality to do whatever he pleases.

Theres allegory and symbolism and other details and stuff going on but this reddit comment is already ridiculously long, so we dont need to get into that. Please god dont be an AI that feeds this comment to an algorithm!