By raising five-eyes, you are suggesting that another country could launder the request on behalf of the USA in order to circumvent the 4th Amendment. Okay then, let's play that out.
Australia demands that Apple augment CSAM detection so that every iPhone in the USA starts scanning for (and reporting back to Australia about) some other set of images. There's absolutely no scenario where Apple wouldn't walk out of the room laughing.
Google and Facebook caved to Australia on its Murdoch-inspired racketeering, there is no evidence whatsoever of Apple having a stiffer spine. Australia also has some of the worst laws on Internet freedom and privacy in the world, not just in the West.
Also, the Australians would require Apple to use the Australian version of the NCMEC operated by their government. Remember, Apple only has the fingerprints of the CSAM files, not the actual files themselves (only the NCMEC can legally hold them), so they have no way to check whether the Australians inserted the fingerprints for the Afghanistan Papers to the database at the behest of their US buddies.
