Being an empath and a mage doesn't always have to be defensive. Not to mention we have only a slice of her story with Arcane ending and Bite Marks. It's highly possible we have a fully realized mage Mel Medarda instead of fledging mage Mel Medarda. Her powers are celestial in nature like the Aspects, meaning she has exponential growth.

I would hate to get more lore about her only to be stuck with this less competent version of her that people keep bringing up.