What's at Stake in the Objective/Subjective Wrongness Debate?

A decade ago I wrote an introductory essay on 'Objective and Subjective Oughts', and the theoretical role of each. In short: the objective ought identifies the best (most desirable) decision, or what an ideal observer would advise and hope that you choose. The subjective or rational ought identifies the wisest or most sensible decision (given your available evidence), departures from which would indicate a kind of internal failure on your part as an agent.  Both of these seem like legitimate theoretical roles.  (Beyond that, various more-subjective senses of ought -- derived from instructions that any agent could infallibly follow -- risk veering into triviality, and are best avoided.)

Now, Peter Graham's Subjective versus Objective Moral Wrongness (p.5) claims that there's a single "notion of wrongness [either objective or subjective] about which Kantians and Utilitarians disagree when they give their respective accounts of moral wrongness."  This strikes me as a strange claim, as the debate between Kantians and Utilitarians seems entirely orthogonal to Graham's debate between objectivists and subjectivists.  More promisingly, Graham continues: "And that notion of wrongness is the notion of wrongness that is of ultimate concern to the morally conscientious person when in their deliberations about what to do they ask themself, 'What would be morally wrong for me to do in this situation?'."

My worry about the latter approach is that our assertoric practices reveal the deliberative question to be ill-formed (in that "correct" answers do not correspond to any fixed normative property).  It doesn't truly ask about the objective or the subjective/rational 'ought', but instead a dubious relativistic (or expressivist) construct. As I summarize (in the linked post):

We effectively end up understanding the deliberative question as having the constant meaning 'What should I do relative to the relevant evidence?' whilst allowing the relevant evidence to vary across assessors. Disagreeing as to what evidence is relevant thus translates into disagreeing about the deliberative question. But there's no absolute fact of the matter as to which evidence really is "relevant", and hence the correct answer varies from perspective to perspective, even when assessing a single token utterance.

[This undermine's Grahams 'Advice Argument against Subjectivism', as our assertoric practices don't merely support fully-informed bystanders advising agents that they "ought" to pick the option that's objectively best; they equally support moderately-informed bystanders advising agents that they "ought" to pick the option that has higher expected value given their (improved but still incomplete) evidence base.]

Is there anything real left for this debate to be about, then?  Putting aside our confusing assertoric practices, we can perhaps still ask what the morally conscientious person is ultimately concerned about when they ask themselves the deliberative question.  But I'm not sure how much room there is for debate over this.  It seems clear that (i) what the morally conscientious person is ultimately concerned about is, as Graham argues, something objective but that comes in degrees, and (ii) their deliberation is properly settled by determining what they subjectively ought to do (as this yields the best prospect for achieving what objectively matters to a greater rather than lesser degree).

Would anyone really disagree with either of these points?  Or is the debate just a confusion that stems from "objectivists" stressing the former point while "subjectivists" stress the latter?

I will say, I find it a bit odd to invoke a deontic concept (whether wrongness or ought) to play the degreed role identified in (i).  We don't typically think of these in degreed terms, so it at least invites the confusion of assuming that the objectivist would try to do whatever has the greatest probability of being objectively right, which mineshaft cases show to be misguided. (Graham instead holds that conscientious agents would choose the "minorly wrong" safe bet in order to avoid the risk of committing a much graver objective wrong.)  I think it would be more natural to appeal here to a non-deontic concept like the objective moral preferability of an option.

Further, I think we can turn Graham's own arguments against him on this point.  In the 'Future Wrongdoing Argument against Subjectivism', he claims that "the morally conscientious person’s concern not to act wrongly in the present just is the very same concern they have to not act wrongly in the future." (49)  But in fact no truly morally conscientious agent can take their future (even "objective") rightdoing as an ultimate end.  As I explain in the linked post:

rightness is an unworthy goal because it is influenced not only by the intrinsic choiceworthiness of the action but also by the capabilities of the agent. This suggests two  very different strategies for acting rightly: One is to perform morally great actions. Another is to stunt your own agency: become irremediably incompetent, and very little can be required of you in future. By manipulating morality's demands in this way, you can be confident in meeting its (now minimal) demands without difficulty.

Surely the conscientious agent would not wish (even pro tanto) to be so stunted.  Just as the levelling-down objection demonstrates that inequality per se is not the right thing to care about, so my Moral Stunting Objection shows that acting rightly per se is not the right thing to care about.  Of the two ways of acting rightly -- acting in highly choice-worthy ways, or lacking the ability to do better -- only the former is something that a truly conscientious agent could take as an end in itself.  So the morally conscientious agent's ultimate concern is not with moral rightness or wrongness at all (whether "objective" or otherwise), but with this more fundamental consideration of objective choiceworthiness or preferability.

If I'm right about this, then it would seem that Graham's debate rests on a mistake.  Or am I missing something?