Realm Encryption, Secure Enclave, and Keychain - ios

Question

Sorry to be yet another post about encryption, but I am struggling with setting up some truly strong encryption in my application. I currently have a basic setup for login that utilizes keychain and is based off of Tim Mitra's tutorial, which works wonderfully. However, I am uncomfortable about storing the account email / username in UserDefaults as it isn't particularly secure. Is there a better method that anyone can come up with? Additionally, I am working on utilizing Realm's built in encryption features, however I am unsure as to how I should properly store the key for said encryption given that it is of type Data. I also have heard that I should double encrypt the user's credentials using Secure Enclave and possibly utilize the same technique with Realm's key. Is there a guide that someone could point me to? How would you better optimize my code to be brutally secure? I have already set the application to check the device for Cydia and other signs of jailbreaking so as to avoid keychain data dumps and plan on checking any / all urls called too.
Here's my implementation of Keychain:
private func setupAccount()
{
let newAccountName = inputFields[0].text
let newPassword = inputFields[1].text
let hasLoginKey = UserDefaults.standard.bool(forKey: "hasSetup")
if !hasLoginKey {
UserDefaults.standard.setValue(inputFields[0].text, forKey: "username")
}
do {
// This is a new account, create a new keychain item with the account name.
let passwordItem = KeychainLIPassItem(service: KeychainConfiguration.serviceName,
account: newAccountName!,
accessGroup: KeychainConfiguration.accessGroup)
// Save the password for the new item.
try passwordItem.savePassword(newPassword!)
} catch {
fatalError("Error updating keychain - \(error)")
}
UserDefaults.standard.set(true, forKey: "hasSetup")
}
Here is what I currently have for Realm Encryption:
private func keyValue() -> Data
{
var key = Data(count: 64)
_ = key.withUnsafeMutableBytes { bytes in
SecRandomCopyBytes(kSecRandomDefault, 64, bytes)
}
return key
}
private func securitySettings() -> Realm.Configuration
{
let key = keyValue()
let config = Realm.Configuration(encryptionKey: key)
return config
}
private func setupObject()
{
do {
let realm = try Realm(configuration: securitySettings())
let profile = UserProfile()
profile.firstName = firstName
profile.lastName = lastName
profile.dateOfBirth = dateOfBirth
profile.gender = gender
try! realm.write {
realm.add(profile)
}
} catch let error as NSError {
fatalError("Error opening realm: \(error)")
}
}
Thank you so much!