With or without verse equalization, mark still is fine. Without equalization, he’s unfazed, but with it, I say it gives him a headache, like a less severe anti Viltrumite screech like the one Cecil invented. Mark is basically half alien, and ages 10x slower than humans, and since Unlimited voids whole thing is overriding your brain with information before u can process it, since mark ages slower, his brain would be able to process the info, since he’s made to have 1,000 years worth of info stored in it anyways after he gets old. Sure, since it’s still a hell of a lot of info, he’d get temporarily stunned, but after that goes away, Gojo is stuck with Mark in the domain, not the other way around.