Is this the point that you are talking about?
Jesus was fully human as well as fully divine. By virtue of His human nature, the literalist reading of “all” in Romans 3 should apply to Him.
Your point is not valid because even when the passage is read literally it cannot apply to Jesus because although He possesses two natures, He is uniquely one person.
Council of Chalcedon (451 A.D)
Therefore, following the holy fathers, we all with one accord teach men to acknowledge one and the same Son, our Lord Jesus Christ, at once complete in Godhead and complete in manhood, truly God and truly man, consisting also of a reasonable soul and body; of one substance with the Father as regards his Godhead, and at the same time of one substance with us as regards his manhood; like us in all respects, apart from sin; as regards his Godhead, begotten of the Father before the ages, but yet as regards his manhood begotten, for us men and for our salvation, of Mary the Virgin, the God-bearer; one and the same Christ, Son, Lord, Only-begotten, recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and subsistence, not as parted or separated into two persons, but one and the same Son and Only-begotten God the Word, Lord Jesus Christ; even as the prophets from earliest times spoke of him, and our Lord Jesus Christ himself taught us, and the creed of the fathers has handed down to us.
Still, you are making an implied exception for Jesus in that “all”. I agree with your reasons, but they do not remove the fact that St. Paul did not write “all but Jesus have sinned”; he let us deduce that. Elsewhere St. Paul did write that Jesus “knew no sin”, so sin is not something that automatically does not apply to Jesus because He has two natures.
So, how about the Holy Innocents, does “all” in Romans 3 apply to them?