Although some Frozen enthusiasts have hypothesized that Frozen 3 will grant Anna powers to match her sister's, there's a compelling reason why that won't happen. Frozen 3 itself is still a pure hypothetical, given that Disney hasn't even discussed making a third installment of its hugely successful franchise. But regardless of whether a full trilogy is ever realized, the idea of Anna having powers simply doesn't work given the revelations in Frozen 2.
In the wake of the original movie's exploration of sisterly love and self-discovery, Frozen 2 develops these concepts further. As Elsa and Anna dig deeper into their family's history and Elsa's continuing feelings that she's not being her truest self, some complicated and in fact rather confusing revelations come to light. But while Frozen 2 suffers from fifth spirit plotholes regarding Elsa's identity and how exactly it works, one thing is stated pretty clearly at the end. As the fifth spirit, Elsa is a bridge between humans and the natural world, and she tells Anna that a bridge has two sides, meaning both sisters are crucial parts of the equation.
It's because of this detail that Anna won't have powers if Frozen 3 ever happens. While it would be intriguing to see the younger sister explore a magic gift of her own, this would go against the concept of Elsa being the spirit side of the bridge with Anna being the human. If both sisters are part of the fifth spirit, as Frozen 2 seems to imply, then they are already two sides of the same coin without Frozen 3 giving Anna fire powers or any other magic abilities. In fact, giving her powers would further confuse the already tenuous explanation of the fifth spirit bridge that Frozen 2 offers.
The fact that granting Anna powers would invalidate or at least muddle the spirit-human bridge concept is only part of the issue. Aside from the logistical problem it poses, a sudden manifestation of magic in Anna would also take away from the beauty of her character. Both Frozen and Frozen 2 affirm Anna's worth regardless of the fact that she doesn't share her sister's magic, and they highlight that she is a strong and capable person all on her own. Much like Kung Fu Panda's message that "there is no secret ingredient," or Disney's newest film, Encanto, in which Mirabel lacks powers, Anna provides a good example for kids that everyone is already worthy without having to prove a fantastical capability. In short, Frozen 3 giving Anna powers would be a mistake because she's already complete without them.
If Frozen 3 does happen, it will have its work cut out for it filling in the gaps and questions left by Frozen 2. Elsa's origin, power, and purpose need more fleshing out, and the other characters like Anna and Kristoff deserve more time to shine. But the one thing Disney needs to avoid doing, in order to resolve confusion rather than create more, is giving Anna powers out of nowhere. As the human half of the bridge, it's fundamental to her character that she's non-magical, and thus the only way Frozen 3 will make sense is if Anna still doesn't have powers.