Not good, they are still able to implement the controversial CSAM by having file checksums and the metadata, the Advanced Data Protection is half baked and still allows Apple to do privacy abusive stuff.
Encryption of certain metadata and usage information
Some metadata and usage information stored in iCloud remains under standard data protection, even when Advanced Data Protection is enabled. For example, dates and times when a file or object was modified are used to sort your information, and checksums of file and photo data are used to help Apple de-duplicate and optimize your iCloud and device storage — all without having access to the files and photos themselves. Representative examples are provided in the table below.
This metadata is always encrypted, but the encryption keys are still stored by Apple. As we continue to strengthen security protections for all users, Apple is committed to ensuring more data, including this kind of metadata, is end-to-end encrypted when Advanced Data Protection is enabled.
iCloud uses strong security methods, employs strict policies to protect your information, and leads the industry in using privacy-preserving security technologies like end-to-end encryption for your data.
support.apple.com