What does only begotten son mean? Begotten in the flesh? Begotten in the spirit? Begotten from the dead? All of the above?
He was certainly the only begotten son of God. born of Mary.
He was certainly the only one who received the full measure of the holy spirit ("This is my son" at his water baptism)
And he was certainly the first born from the dead, which Paul links to Psalm 2:7
God hath fulfilled the same unto us their children, in that he hath raised up Jesus again; as it is also written in the second psalm, Thou art my Son, this day have I begotten thee. And as concerning that he raised him up from the dead, [now] no more to return to corruption, he said on this wise, I will give you the sure mercies of David. Acts 13:33-34