Trump lost the 2020 popular vote by a massive seven million plus votes. A few percent of the Republicans who did vote for him then have since repudiated him after the January 6 insurrection fiasco. I don't see how chosing Stefanik as his running mate brings any of them back, or makes the 2024 election close enough to steal.

We've already had successful and unsuccessful female VP candidates, so Trump wouldn't be breaking any new ground. If people pointed out that Trump was copying McCain (who chose Sarah Palin), that would make him very unlikely to pick a woman, since he loathes McCain so much that he doesn't want to be seen as emulating him.