There is nothing in the above that I really disagree with except the last sentence, but I think there are two distinct points being made. (1) An element of faith is involved in accepting that the original texts have been preserved more or less faithfully; and (2) Even if we were sure we had the original ‘as-written’ texts of Scripture it requires faith to receive them as the Word of God rather than simply the words of men.
In the case of (1) I say ‘an element’ of faith since (as you yourself imply) such matters can be studied by historical and historiographical research. Unfortunately different scholars come up with different answers, so that the interpretation of any factual research findings often depends on the interpreter’s preconceptions (‘faith’?).
In the case of point (2) faith is, of course, fundamental. Do we or do we not accept the original Scriptures as constituting God’s Word — that is, God communicating with us (and thus revealing Himself to us) through the instrumentality of human writers? And if we do accept this proposition, is our faith rational or irrational? You continue: