1. There are many definitive quotes, including within the RotS novel itself, which is where most of Harr and Skillz' Anakin wank stems from, confirming that Yoda and Sidious are the ultimate masters of their respective sides of the Force.
When those blades met, it was more than Yoda against Palpatine, more the millennia of Sith against the legions of Jedi; this was the expression of the fundamental conflict of the universe itself.Light against dark.
Winner take all.
[..]
The avatar of light, Supreme Master of the Jedi Order, the fiercest, most implacable, most devastatingly powerful foe the darkness had ever known…
--Revenge of the Sith novelization
2. While Anakin's rage-enhanced victory over Dooku was emphatic, Sidious' victory over a rage-amped Darth Maul was so emphatic that Maul saw more lightsaber blades than he could count, and then more than that.
And this isn't Sidious fighting at his most desperate hour, this is him taking a comfortable victory over a bloodlusted, raging Maul.
Sidious raised his saber and flew at Maul, who parried desperately, his mechanical legs whirring as he sought to counter his former Master’s blows. Sidious’s sabers were a blur, a whirling cage of deadly plasma. Maul danced away from one blow, then reversed his movement to avoid another, and then there were too many to count, and then there were even more than that.Maul’s saber spun out of his hand, bouncing away across the floor.
--Darth Maul: Shadow Conspiracy
3. A Yoda who was holding back, and trying to convert Dooku to the Light Side, emphatically defeated Dooku on the Dark Side nexus of Vjun, which would amp Dooku and hinder Yoda.
It took Anakin a massive rage amp on neutral ground to begin dominating Dooku, never mind while being hindered emotionally and by a nexus.
"Wish to hurt you, I do not!""That's odd," Dooku remarked. "I intend to enjoy killing you."
[...]
Then their blades clashed together in a lace of fire, green and red: but the green burned hotter. Slowly, slowly, Dooku gave way: and in the dark, drunken Vjun air, Yoda was terrible to behold.
[...]
Pushing Dooku back yet again, blades flashed and flared stutters of light, blood red and sea green. Sweat ran in streams through Dooku's beard as he countered Yoda's every move, and his lips were white.
-Yoda: Dark Rendezvous
So can we please get over this horseshit about Anakin/Vader beating Yoda or Sidious.
His raw power may come close to theirs, on his best day and with the right amount of motivation, but he lacks the skill, experience or focus to direct that power in a meaningful enough way to secure a win. He has no answer for Sidious and Yoda's speed or mastery of the Force, and there's no doubt that they would be able to undermine his delicate emotional state, as Dooku has been able to. Can we also remember that on the Invisible Hand, Dooku briefly brought the fight back to even ground by simply using Dun Moch, until Sidious prodded Anakin onward?