What glory did the Son have with the Father? What Jesus did not say is He had the same glory as the Father thereby making Himself the Father's equal. Also to interpret John 17:5 to show the preexistence of the Son as part of a triune God totally ignores what Jesus prayed in vs. 3.
Also appealing to some who speak Hebrew is simply begging the question. The Pharisees understood Hebrew yet rejected their own Messiah. Jesus is clear in John 17:3 that there is only one true God who He addressed as Father.
However, what glory does the Son have that existed in the beginning with God? The predicted glory of the coming Messiah that is found throughout the Messianic prophesies, which foretell one who will be born of a woman, is a prophet like Moses, who will be God's anointed one, who would be rejected, suffer death on a tree, who God would not allow to suffer the corruption of the grave, and would reign from Jerusalem with the key of David. In other words a man like you and me. There is not a single Messianic prophecy that even hints God’s anointed is God. The glory the Son had with the Father is the glory of the predetermined plan for mankind’s redemption by God’s grace through faith in Jesus Christ.
The Trinity and the deity of Jesus the Christ are based on the traditions of men and depend on semantics and philosophies foreign to God's revealed truth.