TikTok is used for far more than cat videos which is why it's a considered a threat to those in power. There are freely flowing ideas and narratives which they cannot control - except now they are by restricting access to it.

Instagram doesn't have the same culture at all and it's not a substitute. TikTok is a like a digital "third space" for communities, and just like the real life equivilents, is slowly disappearing. People without community are easier to control.