Where is my iCloud data saved

I created my Apple ID in mainland China and turn on the iCloud service, but iCloud in China mainland is operated by a local service provider that gave rise to severe privacy and data leakage concern. After I moved to Hong Kong, I changed the region of my Apple ID to Hong Kong and there is a new T&C to agree (iCloud in China mainland is totally different with iCloud in other country or regions, with the T&C in Chinese only, and third party may have rights to access your personal data, T&C in Hong Kong and other regions are normal ones). Then my concern is that, after I changed the region, will my iCloud data move to other server same as the Apple ID registered in Hong Kong? or the old data is kept on servers in China and the new data since then will be saved on other server? or all of my data will still be saved on servers in China?

I think this is really important, even I am considering to create a new Apple ID but there are so many data and so many purchased items.