Why the need for the Catholic Church? In order to know the truth, and to have the ordinary means of receiving grace, the sacraments.
In your scheme, a person is either a well-catechized Catholic, or a fully-conscious Satanist.
Of course a person in the state of mortal sin cannot PROPERLY worship God, because he cannot, for example receive any of the sacraments of the living. But if he prays, or if he attends Mass, he is certainly worshiping God.
I am saying that people with a certain knowledge of God can worship God.
Your argument is that only those with perfect knowledge of God can worship him at all, and that all those whose knowledge of God is imperfect or partial are idolaters and Satanists. That is preposterous.
Is this what they taught you in the post Vatican II seminary? Nothing about salvation?