recover account with GT

This should help https://support.microsoft.com/help/17875/microsoft-account-reset-or-recover-password

Hello SpencerKlinge,

Thank you for posting on the Xbox forums. We understand that you are interested in learning if you are able to recover an account with the gamertag. The best way to recover an account with a gamertag is to contact the
Xbox Support Team. They will attempt to send a verification code to the security proofs on the account that has your gamertag. You will have to find out which email address or
phone number the security code is being sent to. Once the support agent verifies the account with you, they can provide you with your account information. We will provide steps on how to contact the support team. Be sure to let us know the results!

How to contact the Xbox Support Team:

1. Click the support team link we provided
2. Select Billing & accounts in the category area
3. Select See other options
4. Select How to protect my account
5. Select Show contact options
6. Select Request a call from Support

Hi There,

You need an email attached to your gamertag in order to recover it. Thankfully this support link should help you find your email, which will enable you to get back into your account.

Link: https://support.xbox.com/en-CA/my-account/microsoft-account/forgot-microsoft-account-solution

Recover your account on to the other console. Click the avatar > scroll right > recover account > follow instructions

You need to recover your account to your console first. Go to My Xbox > Avatar box > scroll right > recover account > follow instructions > you're good to go.