Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello, thank you for reaching out to Microsoft Q&A.
Unfortunately, you cannot add an existing Microsoft domain address like (@hotmail.com, @outlook.com, @msn.com, @live.com) as an alias to another Microsoft account.
So, if you would like to add a new alias to your active Microsoft account, go to this link here and select 'Add email' and set it as an alias. (Create a new Outlook email address on the page and set it as an alias)
https://account.live.com/names/manage
To recover your inactive account, you can try the account recovery options mentioned in the Microsoft article here-