Exactly why I simply cannot trust their supposed 'commitment to privacy'. How could you take it seriously when they are willing to play ball with this clear human rights issue? It's madness.

Short answer is we will never know for sure. There is no reason or incentive for Apple to duplicate your data and it certainly breaches an assortment of data protection laws. Nevertheless you data is always one error away from being sent all over the world. Recall the incident when Cloudflare leaked an unknown amount of information to the public, looks like they have suffered very little repercussion given the scope of the leak.

https://blog.cloudflare.com/incident-report-on-memory-leak-c...

On another note, if I get my data on the Chinese datacenter, does this mean my country's government is unable to extract this information from Apple?

If they send a notice to Apple for my data, will Apple refer them to China instead?