Begat? No wonder we have theological disagreements. Evidently we have biological disagreements! ;-)
I trust in the words of Scripture. ,BR />
There may be a little circularity to your argument. IF Sola Scriptura is the way to go, AND IF immaculate conception/bodily assumption are properly de Fide, then it would follow that God would providentially included something about them explicitly in Scripture.
But, arguendo only, IF the Scriptures do, as we maintain, speak authoritatively about the CHurch's teaching charism, THEN believing in Scripture would lead one also to believe in the magisterium, and so to believe what was declared to be de Fide.
So from our side of the divide we do not think that trusting the teaching charism of the Church which was "sent", that is: apostolic, contradicts trusting in the Scriptures.
Now Bro, I can’t let even you get away Scott free with such abject leaps of logic.
tsk tsk.