I installed TikTok as a test and found that it's garbage. If I watched it for 30 minutes a day for a couple months, I would encounter maybe one video per day where I might think "huh, that's neat". Even following/interacting with my interests (which are only covered in the most broad sense) didn't really fix that. I'm sure it works better if your hobbies are really popular like rock climbing or craft beer or Harry Potter. I think there are some really funny creators and that's where it shines the best - comedy. Everything else is treated in a cursory manner that never really delivers.
The vast majority of videos were a complete waste of time and I'm blown away that people can spend more than a few minutes per day watching it. It took at least a couple months to find interesting creators, but they are so few and far between that it wasn't worth it.
For me, Livejournal was addictive, forums were addictive, Twitter used to be addictive. Especially when you stumbled on niche communities. I've never tried Instagram, so I'm not sure about that.