It may seem a minor point, but it's important. His sonship has nothing to do with the incarnation. He is the Son by the virtue of His Person.
It is related to the following question:
When did the Son of God save you?
1. When you believed.
2. At Calvary.
3. From the foundation of the world.
All are true.
There was a point within the time continuum when the Logos became a human being.
Galatians 4:4 But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law,
Before that point in time He was not human. But I don't object to calling the Logos the Son of God because He emanates from the innermost being of the Father eternally.
But He didn't become human until Galatians 4:4.
I am not going to say it anymore.