iPhone 8/Plus Is iCloud the main culprit when it comes to iPhone privacy?

[Puonti]

Does turning off iCloud Photos disabled CSAM detection?
Yes. When iCloud Photos is deactivated, no images are processed. CSAM detection is applied only as part of the process for storing images in iCloud Photos.

https://www.apple.com/child-safety/pdf/Expanded_Protections_for_Children_Frequently_Asked_Questions.pdf#page5

(above quote included for context)

This is the part that changes with iOS15. You are correct about how it is done now (Aug 2021) and has been for quite some time. CASM is only initiated on iCloud uploaded photos, IAW server side processing. This protects Apple.
I'm excited about the new process taking place directly on the device. I have not tested this in the lab, nor will I. This will shift to client-side processing as of iOS15 and has nothing to do with iCloud settings, either on or off.

I believe you're incorrect on this one. The document I quoted from and linked to (further above) is Apple's FAQ for the Expanded Protections for Children - including CSAM detection - which Apple published in response to concerns and objections to their new planned features for the iOS 15 update cycle. These new plans include handling CSAM detection with a process that's split between the device and the server, which the user can choose to disable by not using iCloud Photos as stated in the FAQ. The actual detection process is described in some detail in the Technical Summary they also published:

https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf

I've provided my sources and I'm quoting them and describing my understanding of them to you in good faith.

I'm now requesting that you provide sources that support your understanding of what's going on.

I've tested iOS15 with a completely dead device. The battery will rebound enough to send one bluetooth ping about every 12 hours. On an older device it only sent a BT ping about once every 24-36 hours. Did you have different results? I would be interested in them.

That could be true and you'll notice that I was not disclaiming any of that in the post you're responding to. I was merely pointing out that, from what I've read of Apple's CSAM detection plans for iOS 15 so far, there's no evidence that Bluetooth pinging is involved in the CSAM process in any way, contrary to what you were claiming in your earlier post:

An image passed via AirDrop to you that fails the 'hash-test' will be flagged. Multiple image 'hash-check' failures will send an alert. Alerts can be sent anonymously via bluetooth ping, even if the phone is off AND battery is dead.