Probably the vest. She has a very generic detective sort of look, and that seems to be a common assumption.

the random NCPD activities around the map.

The funniest part of that is that it was clearly someone's "clever" idea for a diegetic way of pointing the player at all these little world mini-events so you don't miss them, then they forgot the system was some formal private contractor thing and included a bunch of things that the cops wouldn't be paying people to go deal with, like there's multiple NCPD Scanner events involving corporate soldiers having murdered some journalist or massacred protesters or striking workers and you get a payout for killing the soldiers and grabbing a copy of their orders or w/e.

I really can't agree with your overall read of how the game handles cops either: every "good" cop either gets killed, driven out, or fired for it, and every time a cop finds their conscience it's because of a direct personal connection to an issue (like the toxic shitbag cops who are worried about their former coworker, the cops you find in the process of murdering some corpo suit who'd put one of their family members into a coma, or the cop in the DLC who dies carrying out a heist of medical supplies to deal with a local health crisis that affected him personally). Like the mission with River ends with the discovery that the NCPD was involved in the assassination and coverup and River gets fired for investigating it at all, then his big rogue investigation thing after that was him looking for a missing family member, leaving him to hit both points of being systemically punished for doing the right thing, and only sticking his neck out to help someone when that someone was a family member of his.