[Campion]

Before the 2nd person of the Trinity became the Son, he was the Word and always existed with the Father,

That's what "eternally begotten of the Father" means. The contrary position, that Jesus is the incarnation of some created demigod who came into existence at a particular point of time, is the heresy of Arianism.

[fortheDeclaration]

The Son was not 'eternally begotten' he was begotten in time.

Begotten means to be created, the Word was not created.

It is those who teach an 'eternally begotten Son' that are teaching Arianism.

The Word was never begotten.

[fortheDeclaration]

Since the Son's birth from the Father occurred before time was created,

So, if the 'Father' gave 'birth' to the Son, that would make the Son less of a God than the Father, since the Son, would have had a beginning, while the Father didn't.