Hello, I need help changing my SWTOR email address

You will need to call swtor support when the lines are open 

This change of email like this can only occur once per account so be sure to not lose access to the account again

I don't quite understand; do I need to call to have XxXCorvoXxX's security key removed so I can log back into my account and then manually change my address?

No you need to call to change the email address on the account, as you need to be able to receive OTP emails to remove the key and change the password 

edit: also confirm the email used on the linked EA account as well

Is calling them the only way to get a security key removed? as I am autistic and being on the phone for something like this experience I really don't like, I tried emailing the EA help twitter and haven't got a response yet

EA help twitter is unable to assist, calling is the only method to change the account email, and remove the key if you dont know the password