But the news networks are on the way out, and tiktoks are in. Do you remember the joyous declarations from 1990s that meatspace state borders do not apply to cyberspace? That was not entirely wishful thinking. The same properties that allow information from "free world" to make way into the "world of oppression" work for different definitions of "free" (democratic, communist, fundamentalist, etc) and "oppressed" (communist brainwashed, capitalist exploitative, sinful and godless, etc). A very similar situation enmeshes cryptography.

Well, China has the great firewall, so information flows less freely from the "free world" to the "world of oppression" than the other way around.

This is so. But places like Turkyie, Russia, or even Iran have much weaker blocks; same applies to much of the authoritarian African regimes.

Basically, to enforce border controls on the internet, you have to break the internet.