Apple Private relay email address

Is there any way of tracking what private email relay address I have used?

When you use an app you can use private email relay address to log in. If for any reason you delete the app and then reinstall the app does the app use a new private relay address for that app? If so you can’t log into an account you previously used because you don’t know the email address you logged into the account with.

Is there a mechanism that can use previously used relay addresses as a log in address?