Video scripts have been near algorythmic for humans already. Does using chatgpt to make your script count as AI made? What if you gave it an outline, walked through it, and guided it to what you wanted - e.g. grammerly?
If you use machine learning to remove background noise, backgrounds in general?
Generated stock images/props/scenes for video essays?
If you made the entire video by hand but use text2speech?
I think that "the script, images, and voice were all chatGPT" is obviously "synthetic", but that's just the extreme. Humans have been using technology to augment their creation abilities forever.
My fear is a large amount of human made content will be called "synthetic" because some specific part used "AI" (which nowadays refers to literally any procedural/statistical/machine learning I guess?)