Autofill/ Keyboard email address suggestion incorrect

Apple support weren’t particularly helpful and didn’t understand what I was asking it seemed- The email suggested here is an old email that used to be my Apple ID 2 years ago. I no longer use it and it isn’t saved anywhere but is always suggested first still!

I have AutoFill disabled, have tried editing contact cards etc anyway, nothing helps!

Signing out of iCloud made it disappear but it returned after logging back in.

This has been asked before and it hasn’t been answered that I can see..

Thanks..