Have you tried logging in to GR using that old email address? You may not have access to the email address for purposes of sending/receiving email, but it seems to me that if you used that email address to login previously (plus a password you hopefully still remember), then it's just a login ID, same as if you'd chosen JaneJohnDoe97.
If that gets you access then you ought to be able to change the contact email and change your login ID.
If that attempt doesn't work (or you've already tried and it didn't work) then the only suggestion I have is to get in touch with the librarians and ask for their help. Unfortunately I don't have a link for them.
Goodreads Librarians are volunteers. They can help with book data, but they are not staff and cannot assist with claiming (or reclaiming) an author profile. If you are having a problem with yours, you'll need to use the Contact Us link on the Help page.
If that gets you access then you ought to be able to change the contact email and change your login ID.
If that attempt doesn't work (or you've already tried and it didn't work) then the only suggestion I have is to get in touch with the librarians and ask for their help. Unfortunately I don't have a link for them.
Eric