One can know the essential mysteries of the Faith without knowing of the sacrament of baptism, for instance, as when St. Thomas gives the example of an angel being sent to a pagan to educate him in the mysteries of the Holy Trinity and the Incarnation.
Impossible to know the essential mysteries of faith, but not know about the most essential of all the mysteries of faith. Your statement make no sense.
So are you saying that you believe that God would send an angel to a "pagan to educate him in the mysteries of the Holy Trinity and the Incarnation" - but not baptize him? How can a Catholic believe such a thing I don't know.