showed he could easily dump almost anyone into the speed force, and was so good at manipulating kinetic energy he could even overcome a high end speedster (the evil version of impulse) in such a way as to suck all of his kinetic energy away and trap him as a statue.
High end showings for him could literally freeze all his enemies in place by stealing their kinetic energy, or dumping them all in the speed force.
Sersi during her Avengers run had some of the best showings in comics. She was able to casually transmute whole teams even overcoming effortlessly Iron Man's tech that specifically protected against transmutation. She turned Eternals into Aardvarks casually, leaving them powerless. She created illusory versions of Ikaris that weren't as powerful as Ike himself, but were able to fight independently.
When fighting Atlanteans, she easily turned half of them to GI's and had them fight the other Atlanteans.
Sprite, who specifically isn't as good at transmutation as Sersi, transmuted all the eternals to normal, powerless humans, across the entire planet.
Here are a couple scans
Here's where she owns Hercules:
So, a top end Sersi just transmutes all of the opponents to something powerless, and even top transmuters have not shown the ability to resist high end eternal transmutation. Fight over before it starts.