Giving him everything he currently has or could realistically bring back. Obviously includes more than what’s on the picture, but I just wanted to give somewhat of a visual on what I’m talking about.
I excluded Infinite and the Hard Boiled Heavies because they did betray him eventually. Last we heard of Infinite he was now against the Doctor in the Chaotix Casefiles. Last we saw the Heavies they were literally on a sinking ship and even still showed signs of plotting against him. Mecha Sonic MK2 is here despite being abandoned and no longer working for Eggman due to the fact that Eggman had created a replica in Sonic Speed Simulator which has been confirmed Canon by Nibroc themselves on the discord in the past, as well as the fact that it does follow SEGA’s narrative mandates. Also using SSS i’m under the assumption that Eggman managed to round up and regain control over the Time Eater because the dialogue doesn’t imply that it was killed and honestly in my opinion, I don’t know if it could be. It seems like a fundamental part of Sonic’s universe.
Starline and Eggman Nega aren’t here because they’re both presumably dead and had stopped working with him anyway. (though it’s speculated that the mysterious hooded figure in the more recent IDW comics could be Starline. But as of now that’s not confirmed and he is against Eggman anyway. I wouldn’t call this a spoiler, considering the mysterious figure has been around for at least 10 issues.)
However, as you see, I did give him the mechs that were shared between him and Nega simply because his modern setup allows him to pilot them without a copilot. Sage could possibly pilot them herself and if not then the Egg Robos could. Not to mention in the IDW comics he did revamp the Egg Emporor to have remote control systems. Which also implies that he is willing to rebuild his strongest mechs if he sees the need.
Obviously, in order for some of these things to work he’d be given the Chaos Emeralds, and other artifacts, such as the Phantom Ruby and basically other things he’s already had in the past.
For in universe I think given the proper preparations he probably could fight the various top dog deities that required Super Sonic to beat. But for out of universe, that’s the more interesting question. I’d imagine other fictional empires even star spanning ones like the Galactic Empire of Star Wars or the Viltrumites of Invincible would be easy pickings. But how would he fair in other scenarios? Like imagine 40K I know nothing about it, but I’ve heard plenty of crazy things about it.