The Catholic Church isn't based on sola scriptura.  You might be happier with a more fundamentalist strain of impoverished/shrunken Christianity, Baptist or one of those.

The priest doesn't confect the Sacrament.  

Remember: Matter and Form of the Sacraments. In the case of Holy Matrimony, 'matter' is the conjugal bond (bond of wills, una caro), and the 'form' are the wedding vows, which the couple express.

The priest is merely the formal witness for the Church.