Well it's still on their website, so the statement stands. Not sure if their stance will change with a new CEO. So far they've been consistent with their user privacy policy.
As a first action, it may help to deactivate the iCloud backup and the app syncs. For general data (documents etc.) you can use Cryptomator, for example, before uploading it to any cloud. Alternatively, a local iPhone backup via iTunes is still possible.
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https://www.apple.com/customer-letter/