I've noticed that when I restore my old iPhone's backup to a new iPhone, 1Password's master-key (which is never supposed to leave the device 1Password is installed on, and you transfer manually), my TOTP credentials (in Google Authenticator or a similar app), the Steam authenticator-key, etc … still seem to exist on the new, restored, device.
This implies that they're also sitting around in my backups — and possibly in iCloud?
How can I back up my device without compromising the uniqueness of my second factor of authentication?