As I understand it, Kantian constructivism is partly a position in normative ethics and partly a position in metaethics. In metaethics, it is the position that ethical claims have truth values, but their truth conditions consist not in a set of objective facts to which they correspond, but instead in the outcome of some procedure of deliberation resulting in decisions about what to do.

Both Kant and Fichte thought of traditions of revealed religion as ways of symbolically (that is, with aesthetic emotional power) thinking about our moral condition. Both thought that religion would become more and not less powerful, emotionally and morally, if the claims of scriptures and religious teachings were taken symbolically rather than literally (whatever 'literally' might mean in the case of claims that are either nonsensical or outdated or historically unsupportable if taken as metaphysical or historical assertions).

Kant thinks we can show that there is no contradiction in supposing we are free.

The species of anti-Enlightenment religion we find among evangelical protestants is far more impoverished, anti-intellectual and downright wretched.

We are generally forced to choose one way or the other of distancing ourselves from Kant. I suppose I tend to choose the irreligious way. But I regret that Kant's path has not been followed.

The problem I see with utilitarianism, or any form of consequentialism, is not that it gets the wrong answers to moral questions. I think just about any moral theory, worked out intelligently, and applied with good judgment, would get just about the same results as any other.

Kant was a rational theologian. He did not pretend to be a biblical or revealed theologian.