Right, it's obviously end-to-end encrypted because if it weren't, everyone would have been screaming for years about how horrendously insecure it was. iCloud K

Right, it's obviously end-to-end encrypted because if it weren't, everyone would have been screaming for years about how horrendously insecure it was. iCloud Keychain is fine, just use a good password. There's no particular harm in letting Apple store an encrypted blob for you on its servers.