The Gospel of Marcion has a really strange construction in Qn 7.28, μείζων γυναικῶν Ἰωάννου. If we simply read it on its face, it says, “A greater one from John’s women.” The following passages in Qn are all about the “sinful woman” (Qn 7.36-50) and then the litany of Jesus’ female followers/patrons (Qn 8.1-3).
Given this context, it seems highly likely to me that Mary Magdalene was originally pictured in Qn as one of many women followers of John the Baptist, one who after John was imprisoned (Qn 7.18) began to follow Jesus as the lead patron of a group of women.
If this is accurate, then it is fascinating to consider that even the previous two verses (7.26 and 7.27) in Qn (50-65 CE) may have originally been about Mary Magdalene, making her a “prophet” (7.26) and the messenger of Malachi 3.1 (7.27) who would prepare the way for Jesus. A couple decades later, in the 80s, LkR1 (the editor of Early Luke aka the Gospel of Marcion) may have transformed these verses to conform to the traditions in the Gospel of Mark about John the Baptist being the “prophet” and the messenger of Malachi 3.1.
However much we can piece together of Qn, it is clear that it had an esteemed role for Mary Magdalene as the one who made Jesus the messiah. Mark and later gospels (including GMarc as a combination of Qn and Mark) essentially displaced and removed Mary Magdalene from the story of Jesus to obfuscate that she was in fact the one who got his messianic ministry started and was his chief and best known early follower.