If there is nothing else, then you as a customer has screwed up with it before, right? And then the entire strategy/philosophy is maybe to be reviewed?!

Or, in other words: If there is no alternative, this is due to your own faults. Either deal with it, or find ways to undo your mistakes.

Alternatives to private messaging on TikTok?

Uh, Signal. SimpleX. Session. XMPP/OTR. PGP.

Discussing things on TikTok, that the government must not know about, seems a bad idea.