> “It IS e2ee.“

Well, not really…:

” 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. ……”

https://support.apple.com/en-us/HT202303

For example, file names in iCloud are not e2e, etc. etc.