I’m thinking it could be active enough to actually obscure the camera recording in real time whenever you are in the frame, like an actual beam that goes into the camera lens making the normal light intake all distorted, so it wouldn’t appear to malfunction or fail, it would just be like a refracting smudge in the feed.

wear a hat/beanie with IR LEDs, you need a few frequencies of "IR", but it's invisible (or barely visible) to humans, but it's the same as shining a light into a sensor to a "machine". could have it built in to a jacket collar, too. you'd have to wear pants to foil gait detection, too. Something with a lot of angles and squiggles that is hard to see as "distinct" against the background.