Okay, so if I understand correctly, the data in those Apple products is not secured, but turning on iCloud on a device does not ruin encryption for other apps that take it seriously. So if I have an app that uses Keychain (end-to-end encrypted) and encrypts it's data properly, it is still secure.

Unless Apple is really bad and somehow collects my keys from keychain, or collects keys passed to CryptoKit, etc., straight out of RAM, and sends them to 3-letter agencies ... if I think that's happening, then I will look for new devices.

I'm not sure I understand your keychain point. With iMessage you can message others with just your iCloud credentials if you turn it on, and you have access to full conversation history - without needing any particular device keys.

> Pixel which encrypt your device backups with on-device hardware encryption.

Can you set up a new android phone from an old phone’s backup? If so, how could this work?

This is a standard way to set up a new iPhone: “restore” from a backup of your previous phone. Especially handy when your old phone is no longer available (lost/broken)

Yes, decryption requires the original device's unlock PIN/pattern/password:

https://security.googleblog.com/2018/10/google-and-android-h...

Not that I fully understand how hard it is to circumvent.

Oh, I see. Apple has done that since the original iPhone too, and I believe iPod before it. I thought you meant they used a hardware key.

For your backups - but once you use iCloud to sync devices in real time, they just use their service keys, and your iCloud credentials are enough to read your iMessage history.