Chinese people cannot have a say on things like Xinjiang in their own country because of the influence of the party over their media ecosystem. We can improve ours significantly, undoubtedly, but I would look more towards Europe than China for alternatives. Germany spent years Nazi proofing their system and so far the results have been not bad.
You're right that in Germany the Nazi problem is now negligible, but the real problem we face is extreme Islamofascist groups (to use Macron's words). In France, Macron banned the Gray Wolves, a Turkish ultra-nationalist group.
But Germany faces a very big problem with the Turkish-nationalist population. Probably more of a threat than France, given that the Turkish population in Germany is upwards of 9%. Even Turkish-German politicians are now calling for a ban on the Gray Wolves and other such extreme organizations (see https://www.msn.com/en-za/news/other/german-lawmakers-urge-b...).
While this ban may go through, the problem of radical Islam will remain a persistent threat in Europe.
I don't know that there's any clear-cut way to avoid extremism while also preserving freedom.
