To be clear, keychain is end to end encrypted including the Cloud Key Vault that backs it up to potentially adversarial clouds. Not true for other iCloud data but your passwords are probably safe.
Need to store photos? Baidu disk and tons of other services provide much larger space with no cost, and much more affordable paid version. Wallet? almost everyone in China uses Wechat pay or Alipay now. Even App Store supports Alipay for purchasing apps. Maybe they can steal my contacts? If so, they would have all my Wechat and QQ contacts already, maybe even all the messages. While I do like more privacy, but it's basically at the bottom of my list of concerns.
People mention "Chinese activists", well, almost all of them don't even live in China. Rest assured their lives are not impacted as well