Now that I've mostly played through the game for the third time now (waiting for the final version of Chapter 11 before replaying that), and since people are chatting about Ivy...
I've grown to appreciate Ivy as a chaos agent. An instigator. A shit starter, if you will. The kind of person that you're glad you know, because they keep life interesting, but you hope you don't know too many of them. She plays that role for Lena as the protagonist (Jeremy and Perry split that role for Ian).
She's not perfect. She's perceptive and driven, but self-centered and inconsiderate. I also think she's making some strategic mistakes with her choices. Like doing erotic material online (Stalkfap) and then trying to join a high-end model brand (Wildcats), which is a transition that rarely happens in that order. But that combo of perceptive, driven, and inconsiderate makes for great fun. She is also humanized by the fact that she at least somewhat cares for Lena (from the prism of her own outlook and values, I don't think Ivy does empathy and perspective-taking).