Nor was the grace given to Mary of a "of a unique kind" as we are "freely given" that grace as well.
Ephesians 1:6 to the praise of his glorious grace, which he has freely given us in the One he loves.
The construct that Mary was "full of grace" or special in any way regarding grace is a construct totally made up by the Catholic Church and is false.
The term used for Stephen is plērēs charitos, meaning "full of grace at that moment."
The term used for Mary is kecharitomene!, meaning "one who's always been filled with grace."
I was asked where in Scripture the Catholic Church has interpreted Mary as being born without Original Sin. I'm pointing out where.