Quite the opposite - The point is made moot, simply because the Protestants, their scholarship wholly disregarding your declarations and magisterium, have come to precisely the very same set of books as canon (NT), in spite of their being vast and varied, wherein that determination has been continually questioned and upheld.
That this argument has been bandied about, over and over, time and again, lends nothing more to the argument, so go to the interwebs and seek it out if you remain ignorant to it's principles.
the “Protestant scholarship” you refer to, at it’s core, relies on Catholic Sacred Tradition. ( of course they aren’t intellectually honest enough to put it as bluntly as i did )
No Protestant has ever been able to determine from the Scriptures themselves what comprises the canon.