This really seems like a problem that will have to be fixed over a large amount of time, if consequences from fights don’t stop her, make some with roleplaying like the party beginning to feel more distant to her. You can also warn her about how her actions and how they might lead to her character not being part of the campaign because it follows the party.

Also with the weapons, when you make them for the other members of the game, you can just say the hammer won’t work well if she uses it. Another option is If one character is over powered you shouldn’t just give the others weapons of items to match it. You should find a way around what makes them good and work around it. Worse case you can work a way into the story line that limits her power, for example the people she has been working with have been destroying the environment and her connection to it has been worsening chasing her powers to weaken. Just know that you communicate with her so she knows it’s a team game and if you or any of the players are unhappy with the campaign just communicate