I think too much gets made of addiction in a soft sense and not enough in a hard sense
If I log off Facebook and it starts spamming me with fake notifications, it's addictive in a way that's more than just "Facebook provides a great service! I'm on it all the time! It's so addictive! :)"
If feeds were chronological and they didn't blatantly lie to your face, or you got messages on time (they like not sending it to you by email) it wouldn't be addictive in a lab rat style
(This is Facebook, not TikTok, but still. And yes, I know TT tries to be addictive on purpose)