Kant did not demolish the Ontological argument. Hartshorne demolished Kant.
After reading many formulations and objections to the ontological argument for the existence of God, I came to the conclusion that I was wrong believing Immanuel Kant vanquished it. This is due to Hartshorne’s formulation.
"Classic interpretation [of the Ontological argument], just as Kant argued, cannot carry existence as a predicate because it simply states that God exists. However, modal coextensiveness’s existence is always a predicate, because modal co-extensiveness says that God is contingent or necessary, which describes how he exists, rather than stating that he does. Describing how something exists adds to the thing itself, and thus Hartshorne’s [Ontological] argument is able to avoid another objection that the classical interpretation cannot. "
— Joshua Ernst, Charles Hartshorne and the Ontological Argument