I think there is certainly a Kantian proximity here insofar as both approaches attempt to derive normativity from structures internal to rational activity rather than from external preference or empirical desire.
Where I suspect the route differs however, is that my concern is less with autonomy or self-legislating rational will as such, and more with the constitutive conditions under which considerations can function as reasons at all without collapsing into arbitrariness.
The pressure as I currently see it, is not merely that rational agents must universalise maxims, but that the authority of reasons itself appears undermined if justificatory standards depend solely upon standpoint privilege or brute numerical identity absent a relevant normative difference.
So the transition toward ethical constraint would arise not from an independently posited categorical structure, but from the requirements of non-arbitrary justification internal to intelligible rational agency itself. The bridge from normativity to ethics is precisely where the deepest pressure of the is–ought problem remains, and I would not claim the transition is automatic merely from the existence of norms internal to rational judgment.
My thought however, is that once considerations are treated as genuinely justificatory reasons rather than as expressions of brute preference, rational assessment already appears committed to standards of coherence, non-arbitrariness, and justificatory consistency.
For example, if two agents are relevantly similar with respect to the formal conditions under which considerations function as reasons; it becomes unclear how one agent could justify treating its own standpoint as possessing uniquely authoritative status solely because it is its own. Numerical identity alone does not seem sufficient to ground a justificatory difference.
From there, the constitutivist pressure is not merely:
“If you want to reason effectively, follow these norms,”
but rather:
“To treat considerations as reasons at all already seems to commit one to standards of non-arbitrary justification that cannot coherently be restricted to one’s own standpoint without undermining the authority of one’s own reasons.”
If standards governing reasons must apply across relevantly similar agents in the absence of a relevant normative difference, then the permissibility of action increasingly appears dependent upon interpersonal justifiability rather than merely private preference.
On this view, moral constraints would not arise externally to rational agency, but from the constitutive standards governing how agents, as bearers of reasons with equal formal justificatory standing, may permissibly treat one another at all.
I am arguing that the rejection of arbitrary standpoint privilege and the requirement of interpersonal justification are already implicit within the structure of rational agency itself.