change the john doe email address

You should be using your own profile and not someone else's.

You will need to log in with your own profile account.

By the looks of the issue you are having the console is pre owned and still has the original owners profile on it.

You will need to add your own Microsoft account to the console. Here's how

1. Press the Xbox button to open the guide.
2. Select the gamerpic in the upper-left corner of the screen, move all the way down and select
   Add new.
3. Enter the email address for the Microsoft account that you want to add, and then select
   Enter.
   
   Important Make sure that you do not select
   Get a new account, unless that’s what you want to do. If you select this, you will create a brand-new Microsoft account.
   
   If you’ve forgotten which email address is associated with your Microsoft account, see the
   
   Lost Account Solution.
4. Enter the password for your Microsoft account that you want to add, and then select
   Enter.
5. Read the Microsoft Service Agreement and Privacy Statement, and then select
   I Accept.
6. Follow the steps to configure your Sign-In & Security preferences to add your Microsoft account to your Xbox One console.

Strange is it your gamer tag or someone else's?

It sounds like you have a pre owned console, which still has an account on it from the previous owner.

In regards to not being able to sing into fifa 20 ultimate, are you trying to sign into it with the account that purchased it?