It seems to me that moral anti-realism, by which I mean that no judgments of intrinsic value are true, implies that nothing is intrinsically better or worse.
I think all that would follow from the truth of moral anti-realism is that no judgements of intrinsic moral value were true. It would not follow from the truth of moral anti-realism that no judgements of intrinsic aesthetic value were true, for instance.
If moral anti-realism is true, then can we have moral experts in the sense of people whose moral judgments are better than others' ? (This is how I interpret your question.) One might suppose not - on the grounds that expertise presupposes a body of knowledge, but in denying truth to morality as moral anti-realism does one denies knowledge too. If no truth, then no knowledge.
Suppose, however, that for the purposes of convenience in social life, and the practical usefulness of normative principles and prescriptive rules of conduct (convenience and usefulness having no association with truth), we adopt a moral code. To repeat : no-one supposes it or the moral judgments it yields to be true. Morality is purely conventional but still convenient, useful or even indispensable.
Assuming such a morality, there could be moral experts. How so ? We still have at least on occasion to think out what to do. Consider this extract from Peter Singer :
This 'thinking out' is a difficult task. It requires, first, information.
I may, for instance, be wondering whether it is right to eat meat. I
would have a better chance of reaching the right decision, or at least, a
soundly based decision, if I knew a number of facts about the capacities
of animals for suffering, and about the methods of rearing and slaughtering animals now being used. I might also want to know about the effect
of a vegetarian diet on human health, and, considering the world food
shortage, whether more or less food would be produced by giving up
meat production. Once I have got evidence on these questions, I must
assess it and bring it together with whatever moral views I hold.
Depending on what method of moral reasoning I use, this may involve
a calculation of which course of action produces greater happiness and
less suffering; or it may mean an attempt to place myself in the positions
of those affected by my decision; or it may lead me to attempt to "weigh
up" conflicting duties and interests. Whatever method I employ, I must
be aware of the possibility that my own desire to eat meat may lead to
bias in my deliberations.
None of this procedure is easy - neither the gathering of information,
nor the selection of what information is relevant, nor its combination
with a basic moral position or the elimination of bias. Someone familiar with moral concepts and with moral arguments, who has ample
time to gather information and think about it, may reasonably be
expected to reach a soundly based conclusion more often than someone
who is unfamiliar with moral concepts and moral arguments and has little
time. So moral expertise would seem to be possible. The problem is
not so much to know 'the difference between right and wrong' as to
decide what is right and what is wrong. (P. Singer, 'Moral Experts', Analysis, Analysis, Vol. 32, No. 4 (Mar., 1972), pp. 115-117 : 116-7.)
As long as we index 'the right decision' and deciding 'what is right and what is wrong' to the purely conventional moral code, and make no presumption of truth, it seems to me quite evident that some persons may be able to collect, collate and apply relevant information and connect it with moral arguments and judgments more efficiently, i.e. with greater expertise, than others.
Should we allow fishing for pleasure ? If part of our moral code is that we should not cause unnecessary suffering, one kind of moral expert would be someone who was knowledgeable about the neurophysiology of fish, could assure us that fish do suffer when caught, remind us that we should not cause unnecessary suffering (thus 'connecting' relevant information with morality) and produce the 'expert' judgment that we should not allow fishing for pleasure.
None of this assumes the truth of morality. On the contrary. It is fully consistent with moral anti-realism. But within a non-truth-based morality it still finds a place for moral experts.