I no she’s not an apostle but they also say she not the not the prostitute and they quote st. Thomas Aquinas who called her the apostle to the apostles.
Right, St. Thomas was using the term loosely (as meaning on who is sent out as an emissary) and combines it with the technical term for the Apostles. So it's like a play on words. St. Mary Magdalene was sent to announce the news of the Resurrection to the Apostles.
It's like with other terms in the early Church that took on very precise theological meanings.
Original word for "priest" was simply an "elder".
Original word for "bishop" was simply an "overseer".
But these were ordinary words that were adopted by the Church and given theological meaning.
We have that today even. So, for instance, the word "grace" has a common ordinary meaning. But when used in the context of Catholic theology, it has a very specialized theological meaning. So also "charity". This kind of thing was already happening in the early Church, where common terms were being given very precise theological meaning. And the Modernists deny this, and so claim that the early Church had no concept of a "priest," except that they were "elders" in the community. That's complete garbage, since there are records of very YOUNG priests from the beginning. They were considered "elders" in a spiritual sense, as part of a spiritual hierarchy.
What these Modernists do is the equivalent of the following. Let's say there was a worldwide catastrophe, and a thousand years from now archaeologists discovered some Catholics texts talking about "charity". Because they are unacquainted with the theological context, they claim that this word just means "generosity".