This form of content is bad regardless of platform.
The problem with TikTok isn't the form, which is effectively StumbleUpon for short-form video (or Dave Winer's "river of news" in video form, if you prefer). There's brainrot content on all platforms, but there's also ArtTok, BookTok, CraftTok, EduTok, FoodTok, GardenTok, HistoryTok, MathTok, MusicTok, PoliTok, ScienceTok, TechTok, and lots more.
Unlimited skipping until a video is sufficiently stimulating had a negative impact regardless of the content, while people limited to ten skips in ten minutes did not experience a negative impact. This suggests that the format itself has harmful cognitive effects.