How can I forward my emails without a copy in my account?
To forward all of the email for an address to another account, do not create an email account for that address. Instead, only create a forwarder.
For example, to deliver all of the mail that is sent to
firstname.lastname@example.org, without any emails saved in the
email@example.com account, add a forwarder from
firstname.lastname@example.org and do not create the
email@example.com email account.