“Apple created its own proprietary alternative, NeuralHash, which apparently wasn’t as good. So Apple U-turned on its efforts to scan for CSAM in its cloud storage. Instead, Apple implemented end-to-end encryption for iCloud files.”

Wasn’t Apple’s design to explicitly NOT scan in its cloud storage, but look at the file on-device at the moment you wish to upload it to iCloud? This method would make it compatible with Advanced Data Protection; so ADP could have always been in the pipeline rather than Apple u-turning. In fact, NeuralHash may have been proposed because Apple wanted to introduce ADP and saw a potential problem here/get concerns from government agencies about it and saw this as a means to an end(-to-end).

The system was designed pretty elegantly and offers far better privacy protections - including guardrails - than what Microsoft and Google do, but the communication from Apple about it was absolutely horrible and generated enormous backlash. (Not saying I agreed with implementing it, just saying the design was infinitely better than competitors.)