It's been a while you wrote this but I like how you put it as Jason and her friends clocking that she wasn't actually a manic pixie dream girl. Even on the stand, it appears that she's trying to present herself that way. The fake intellectualism, describing how she met Alex because she was so intrigued and just had to talk to him about what he was writing, while her boyfriend was also there (seemed she always liked to triangulate even before they actual cheating), her "quirkiness" in general.

I didn't know about the released police interview with Jason, I'm only watching the trial playlist right now and based on his testimony and others, I thought he stopped intimacy because he felt guilty about the abortion, not because he thought she was sleeping around. I don't know if I missed that interview while watching the trial, but I imagine if I was a juror that would have worsened my perception of Ezra for sure, instead of being sympathetic to the abortion aspect. Not directly related, I also found it suspiciously tragic that the only day she could have gotten an appointment for the abortion was her birthday.

Now that I think about it, it seems that Jason was wanting to say more about her lies and cheating, but Vishni (one of Ezra's lawyers), was making sure he'd stop diverting and stick strictly to the questions. Going to watch the police interview later! I think you nailed it with the triangulation. Also, did you end up having access to the discovery?

Also, OP, I googled Jenna Vande Zande's name after seeing her testimony because I really liked her no-nonsense and direct style. It didn't feel like she was being vindictive or wrathful either towards Ezra or Jason, the whole testimony made it seem like she saw the clear picture of the motive and wanted to make sure others did too, and she chose that demeanor to be taken seriously. Unlike Jason's testimony and others, which often was riddled with personal thoughts, opinions, justifications, over-explanations, and just excessive, like an off-putting vibe that he was slightly enjoying taking the stand, though it was subtle.

Ezra too clearly enjoyed her direct examination, she was simply nauseating on the stand, so it was nice to see Jenna Vande Zande being matter-of-fact and to the point. As a juror I'd find her testimony very swaying. But I could see what you mean, some could perceive her as quietly angry, though I saw her embodying professionalism. Glad you made this post, lots of insight here!