My e-mail address got deleted for inactivity. How to recover Xbox account connected to it?

usually you can't, once deactivated they are usually gone for good, you could try calling Microsoft support to see if they can assist, also the Xbox account is not separate, it is the Microsoft account.

So it doesn't matter if you spent 1000€ on games in there, they have the right to delete your account just like that?

Hi and thanks for reaching Microsoft Xbox gamer's community. My name is Josef.
I'm an Independent Advisor and a Microsoft Xbox user like you.

Hope you're doing great today Hugo

If the Microsoft account linked to that Xbox profile was deleted permanently. Unfortunately all the contente associated with that account were deleted as well

Any kind of content or profiles transfer Microsoft accounts can't be made due to security reasons

usually you can't, once deactivated they are usually gone for good, you could try calling Microsoft support to see if they can assist, also the Xbox account is not separate, it is the Microsoft account.

Xbox support cannot totally delete an account, it is an automated process that they cannot interfere with, only happens after a long period of inactivity. If you want to close an e-mail address, change the MS account tied to your profile to something else,
this free's up the e-mail address so you can delete it! Here is how.

support.xbox.com/.../manage-microsoft-account

If your account has been inactive for over 2 years it may have been deleted. For general consumer accounts, Microsoft only retains inactive accounts if:

• you have an outstanding amount payable.
  
• you have a positive account balance.
  
• you have purchased digital licenses associated with the account.
  

That said, your only option for account recovery is the recovery form. You do not need access to any specific e-mail address for the recovery process, you just need to nominate an address at which you are contactable and supply sufficient information to validate your account ownership. If you do not at least know the Microsoft Account's e-mail address though, you have no avenue to recover the account.

Regards,
Jason