Lol @ Bill still being rated so high. Such poor reasonings for his levels. His "strength" is entirely relative if we base it around character statements, and his durability isn't even proven to scale. Bill is entirely self-destructive and paradoxical, so we can't take his cockiness as a veritable source. Hell, remember when he controlled Dipper's body? He actively wanted to feel pain.
I can see the connections of both character having the means of producing a gradual destruction of reality, except Dimentio was actively sustaining the Void even after death, while Bill's little rift was a mere side-effect of his presence. His madness mixed with the anomaly to cause a rip in reality that he made persistent due to his subconscious hax eroding time and space. Reality was being torn apart by a residual effect he didn't seem to have much control over. Time Baby was wprrued because it would've everntually ended everything, but Bill was too caught-up in his head and partying to heed his warnings. We have absolutely no proof that he would've survived and all the evidence to show that he DIDN'T have a plam for the future and that he wasn't aware of the mess he would cause, and even if he did survive, it's clearly more of a hax than destructive power. His premonition of the future he had when he became free had the universe in tact, mind you, so he wasn't aware of how self-destructive he'd be to his own plans for their universe from the start, and even after his death, the rift closed, but it was undoing his magic and hax, and again, the rift was already a gradual process. He isn't inherently that high. Dimention has a pass because he was certain he would have existed past the multiverses destruction, and the invincibility plus Dark P lends credemce to tbat, I believe. However, the heroes and the Oire Hearts power-up allowed them to breach the bounds of imvincibility and harm this multiversal maniac while he was able to harm them in return, thus legitamizing his AP. Bill doesn't exactly have such luxuries.
Even Axolotol said to "blame the arson" because he likely caused the complete disarray of his previous dimension through likely no fault of his own and due to his curse of slowly erroding his environments like a small ember blossoming into a fire when in a wooden environment.
And again, like I've said before, it's more of a passive hax than pure attack potency, and if his durability were that high, than he has some pretty good anti-feats for it, making him an entirely flip-floppy cjaracter in regards to what stats hold credemce. He already had little to work with, and in that iota of time, he did a LOT of unimpressive things.
But whatevs. With the stats given and powers attributed to these cjaracters, Bill likely would win based on yoir standings and criteria.