Some nits: Apple could access many classes of data stored on iCloud by default (including any photos), even now, but you can make almost every class end to end encrypted now if you explicitly chose to. Previously, and by default now, it’s Apple policy and internal controls over the keys your data is encrypted with that protect that data, not the encryption itself (though you can opt in to the encryption itself protecting you from Apple). From what I understand, Apple is only known to actually scan iCloud mailboxes regularly, with the on-device scanning having never been implemented. Outside of nits, considering the delay between the proposed scanning and offering of a wider E2EE program for iCloud, I doubt the two are actually related myself.