This is why people in your church worship Mary and think they are honoring God by doing so.
Events after Mary's death, such as her assumption; the developemnt of doctrine such as the clarification of certain verses pointing to Purgatory, or proper form of venerating Mary are indeed not spelled out for your satisfaction in the scripture.
Because they aren't there.
A couple simple things clarifies the issue of the Marian heresy. John was given responsibility to care for her. John was the last Apostle to die. Mary died before John did. John wrote the last book of the Bible. If any of the things claimed about Mary were true John would have written about them. He didn't.
Nor does the Catholic Church subscribe to the notion that every doctrine has to be found in perfect formulation in the scripture.
And now you have a heresy being accepted as good and true.
He did, Rev. 12 is all about Mary.