Vaggie is probably the most wasted character of any of the major cast, on paper she has a good amount going for her, being the princess of Hell's girlfriend, has only been in Hell a couple years so could serve as an audience surrogate, and of course is secretly a former Exorcist who was one of the best ones according to Adam.
But in practice her relationship with Charlie is codependent as fuck (and no characters call her out on it, so I feel the writers might not even realize it given how unsubtle the show is), and her being a fallen Exorcist is literally just used to make Charlie angry at Vaggie for a single episode, the rest of the hotel nor Carmillia remotely give a shit that Vaggie has killed thousands of Sinners.
Said it before but the reveal of her being an exorcist should have been a mid season 2 twist, she's forgiven by Charlie rather quickly because Charlie is all about second chances, but characters like Angel, Husk, and Pentious treat her like the plague and it's not until the season finale do they begin to forgive her for the things she's done.