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...