Every generation has been saying some form of this about the next generation. If there is "moral decay", you'd expect shoplifting to go up, for instance. The crime statistics don't seem to support that narrative.
Tiktok isn't degeneracy, it's exactly what you expect to come out of a capitalism infused ad-based economy. It's a hostile market for your attention, what did you expect? Things that are entirely fueled by economic incentives and interests are not moral decay. The US has been like this since the very beginning. We literally promised the south not to ban slavery for a long time because otherwise they would not have voted to join the Union because it would hurt their economy to not own black human beings