Apple has never done any scanning server side to avoid abuse and protect privacy. All Photo Library scanning for memories, faces,… is done client side. That’s why your new phone gets so hot and uses so much battery the first few days.Actually Apple has scanned iCloud for years already. However, there is one massive difference here. First of all Apple intends to do the heavy lifting client side in the future. Easily searchable database within a device makes mass surveillance effective. Also companies such as NSO Group will most likely find good use for such database. It’s worth mentioning that on hands of companies such as NSO Group iOS has more holes than Swiss cheese. Tens of thousands of people have had their security compromised by NSO products (that’s only one company). Making device security even worse is definitely not the way to go. Apple should do the scanning on server side like they have done before (and like others are doing) and make the devices safer and more secure. Building backdoors into devices is definitely not the right way to go.
The weird thing is that now they’ve expanded scanning to CSAM, their choice to do it client side sounds worse than server side. They probably should have reconsidered this.