Here’s an article discussing an exploit for pre-2008 MacBooks: https://www.washingtonpost.com/news/the-switch/wp/2013/12/18.... It involves overwriting the firmware of a microcontroller on the camera daughterboard. Or course Apple insists that the camera can’t turn on without turning on the light: https://support.apple.com/en-us/HT211148.

I’d be surprised if state actors didn’t already have this kind of capability, but you also have to trade it off against the degree to which you are or are not a high-value target.