Begotten Son means God’s offspring hence the title Son of God and the word begotten.
For a very short time. the Word submitted to His Father in all things and took on the role of a son.
The incarnation of the Word was a divine act of humility.
Not even the apostles understood the identity of the Christ for some considerable time.
Yet, we know why we exist and the true identity of YHWH.
John 1:1-3
In the beginning was the Word, and the Word was with God, and the Word (Jesus) was God. He was in the beginning with God. All things came into being through Him (Jesus), and apart from Him not even one thing came into being that has come into being.
Colossians 1:16
For by Him all things were created, both in the heavens and on earth, visible and invisible, whether thrones, or dominions, or rulers, or authorities, all things have been created through Him (Jesus) and for Him.
All things that exist were created by Jesus and were created for Jesus only.
The God of the Old Testament was the Word, was Jesus Christ.
Jesus was the perfect image of God while in His human form, stripped of His Glory.