Whatever the early Church thought about Mary it got from the Scriptures directly, from Old Testament prophecy and from New Testament typology, particularly Revelation 12 and the implications of what it meant to be the “New Ark” and the “New Eve”. Read the Church Fathers on this.
The idea that it was merely lifted from paganism is pure poppycock and historical revisionism.
And I don’t think the Reformation understood Augustine quite as well as it thought it did...else it would not have embraced errors he roundly condemned, such as the denial of free will.
There is ABSOLUTELY no scriptural evidence to even hint that people are to pray to Mary, let alone worship her. Why don't you worship Moses? Or Ruth? Or Esther? Or Abraham? Catholics may try to dream up reasons that they should pray to dead people and worship them, but in the end it is nothing more than idolatry. It is no different than worshiping Buddha or praying to Muhammad.
Anything that takes away glory from the Son is pure evil and blasphemous regardless of where it is coming from.
As far as "free will", there is only God's will and man's will. God's will is good and perfect. Man's will is bad and defiled. Man cannot do God's will unless God empowers him to do His will. This isn't rocket science but it sure seems to be hard for people to understand this.