1) its only scanned on upload to iCloud, so if you don't upload then its not scanned
2) (per another article, https://techcrunch.com/2021/08/05/apple-icloud-photos-scanni...): Most cloud services — Dropbox, Google, and Microsoft to name a few — already scan user files for content that might violate their terms of service or be potentially illegal, like CSAM.
So you really can't opt out unless you avoid all cloud photos
Just because Techcrunch says it's so, does not mean it is true. My understanding of other services is they might not scan contents that are not shared. Techcrunch does not have first-hand knowledge of this topic and the other clouds are not explicitly saying they do or do not.
If those other services do it on their own computers I'm fine with that. I never expected privacy from them. I don't want my CPU, battery time and network bandwidth to be used for this.
1) its only scanned on upload to iCloud, so if you don't upload then its not scanned
2) (per another article, https://techcrunch.com/2021/08/05/apple-icloud-photos-scanni...): Most cloud services — Dropbox, Google, and Microsoft to name a few — already scan user files for content that might violate their terms of service or be potentially illegal, like CSAM.
So you really can't opt out unless you avoid all cloud photos