People of a profound initial bias will, in general, believe anything that supports that bias, and reject anything that challenges it, in both cases without any real consideration or thought whatsoever. So I don't think examples of individuals being "misled" by e.g. AI generated images or video, to extremes, is entirely realistic. Rather they were already at those extremes and will just eat up anything that appeals to those extremes.
To take a less politically charged example, imagine there is fake content 'proving' that the Moon landing is faked. Is that going to meaningfully sway people who don't have a major opinion one way or the other? Probably not, certainly not in meaningful numbers. And in general I think the truth does come out on most things. And when people find they have been misled, particularly if it was somebody they thought they could trust, it tends to result in a major rubber-banding in the opposite direction.
To take a less politically charged example, imagine there is fake content 'proving' that the Moon landing is faked. Is that going to meaningfully sway people who don't have a major opinion one way or the other? Probably not, certainly not in meaningful numbers. And in general I think the truth does come out on most things. And when people find they have been misled, particularly if it was somebody they thought they could trust, it tends to result in a major rubber-banding in the opposite direction.