And to answer the second part, she can make her own artifacts by visualizing them, but she prefers to use already created artifacts for a few reasons. First, her artifacts safe just as limited as the real thing, she she would need to spend months, if not years, fine tuning it before it even kinda worked. Second, it's dangerous, especially since it's her own magic that implodes if she screws up, not just some enchanted metal.
That's the limit I outlined. To be able to replicate an artifact she needs to know EXACTLY how it works, she can't just know what it does, she needs to study the original in extreme detail to figure out how it does it, what spells were placed on it where, what materials it's made of etc etc. She has to know the attract she's making as well as she knows her own body.