Just like https certificate authorities, the only way to fight all the AI slop will be "trusted" camera firmware that signs every image with a full chain of trust that the output was a real physical video taken will a real device at a real location.
Most of these are very impractical for the average person. Nobody is constructing lenses just to fake some ai videos. Usually it's good enough to just deter 99% of the population from the crime. If a bit of AI slop gets through that's fine.
For important photo/videos, there will naturally be more scrutiny, and a camera signature won't be enough. For example maybe the photographer would have to embed their identity in the photo. So if they are ever caught making ai photos, all their previous media is invalidated as well.