Agree, but Weir isn't very good at writing women. I'm glad that he kept her character relatively simple and as a sort of driver for the narrative. Had he attempted adding more depth she'd end up in a cringey love triangle or something.
Eva doesn't need more depth, that's not the issue. Her interactions just aren't believable. It's not a gender thing, either, because I wouldn't believe a male version of Eva.
Maybe because I can't believe that someone would ever have that much power and be a jerk at the same time?
IMO, I found her character "lazy" on Weir's part. I wish he tried a little harder to make her easier to believe as a real person.