I've worked in mobile development before. We hide the traffic by batching it, sending it through i.e. Google Play Services (so it looks like Google traffic), or simply sending it all to a relay server so it doesn't look diverse. In any case, all your apps are doing this, and the ones that want to hide it, can.
Tik Tok likely isn't going anywhere, they'll sell to someone able to keep it up and running. The Tik Tok allowed in China isn't the same one, so they don't have to worry about data being pulled from their citizens.
Why do you think that? That's an aggressive claim. I don't use it, but thats because it isn't my idea of fun, obviously many like it. Data collection happens everywhere, are you referring to kids eating tide pods or something?