There is no objective absolute morality that exists in a vacuum.

No, that's highly contentious, and even if it's true, it doesn't grant a license to promote any odd utility rule as ideal. The anti-realist also may have reason to prefer a simpler version of morality.

Utility theory, prisoner's dilemma, Occam's razor, and many other mathematical structures put constraints on what a self-consistent, formalized morality has to be like. But they can't and won't pinpoint a single formula in the huge hypothesis space of morality, but we'll always have to rely heavily on our intuitive morality at the end. And this one isn't simple, and can't be made that simple.

There are much more relevant factors in building and choosing moral systems than those mathematical structures, whose relevance to moral epistemology is dubious in the first place.

That's the whole point of the CEV, finding a "better morality", that we would follow if we knew more, were more what we wished we were, but that remains rooted in intuitive morality.

It's not obvious that we would be more likely to believe anything in particular if we knew more and were more what we wished we were. CEV is a nice way of making different people's values and goals fit together, but it makes no sense to propose it as a method of actual moral epistemology.