If you lose access to an Apple private relay or "hide my email" account and need to update your email to a new one, follow the steps below.
Change your forwarding address
On your iPhone, go to "Settings", then tap your name
Tap "Sign in with Apple"
Select "RentRedi", then tap "Manage Settings"
Tap "Forward To", then select the email address that you want to use.
When you choose the email address, this applies to email from all apps and developers using Hide My Email.