A substantial point of Rev 12 is Mary was seen in heaven. Not only does scripture say so but also does the histories of the church.
Just as it was not wrong for Christ or the Apostles to converse with a dead man on the mountain, a man who at the time it happened was said by Holy Scripture to be dead and nothing in sacred scripture then extant said otherwise. That Moses can appear and converse about things happening and things to come and yet it not be necromancy is a clue.
If the disciples held to the view you do they would have been forced to conclude Christ was a necromancer, and of course they didn’t.
As to Mary being dead, not even the patriarchs are dead. He is not the God of the dead but of the living. And even Abraham saw the day of the Christ and rejoiced when it happened.
Seek YHvH in His WORD. Read all the words in the chapter with
shalom b'SHEM Yah'shua HaMashiach
the illumination of the Holy Spirit.