Im gonna address this one last(I hope) time, Tempest.
Lets go through this again and you tell me where you disagree(or think the text disagrees).
Vitiate was put on his ass at first because he had his guard down. He had his guard down cause he diverted much of his strength on dominating Revan's mind. He diverted much of his strength on that because he assumed he could do it casually but when his attack faced resistance, he had to invest more and more into his TP attack which failed due to reasons that has no relevance when comparing power.
Choosing to take care of someone by dominating their minds instead of fighting them is an indication of superiority as it is a way of dealing with them without even fighting and Revan survived the attack only because he had mastered a technique based on their past encounter. Vitiate is defined by fear of death and avoiding risk so if he attempted such an attack which eventually made him lower his guard, he only did it cause he believed Revan was not a real challenge for him.
"The Emperor rolled over, lifted himself up on one knee, and his hands flew forward as he hurtled a bolt of dark side lightning at his enemy."
Hurtled is the key word there. A cocky TP attack followed by a hurtled attack shows that Vitiate still not going all out on Revan as it also shows that a hurtled attack was enough to stop Revan's charge and send him back.
At this point, we have a Vitiate who until a couple seconds ago believed that Revan was a weakling who could be taken care of without fighting and was sent back with a hurtled lightning attack. So it is only natural that he though 3 more of those small attacks would do the job.
Until this point, Vitiate's actions are not a representation of his true capabilities and after that point Vitiate instantly one-shots Revan.
This is an arena type all out no morals fight where both sides would unleash their full power and Vitiate is indeed more powerful than Galen. He won't finish him off as easily as Sidious did no doubt, but he will still win. 👆