Merging 2 Microsoft Account

Hi,

Here is my situation:

I have my private domain that I use for email address. Let's say my email address is *** Email address is removed for privacy ***

I used to use this email address as my primary Microsoft Account. So I had an account with the username *** Email address is removed for privacy ***.

I no longer use that account. Recently I have created another regular account under outlook.com which I use as my primary account. Lets call it *** Email address is removed for privacy ***.

I want to merge the 2 account for the following reasons:

I have no need for 2 accounts.

My old account has 25GB as the new one has only 7GB.

It would be nice to natively send mails and sign in as my email address *** Email address is removed for privacy ***

I assume the "Aliases" feature does this? I tried signing in to my *** Email address is removed for privacy *** account and adding *** Email address is removed for privacy *** as an alias but it says that address is already taken. Should I close *** Email address is removed for privacy *** account first?

Is there another way besides aliases?

How much storage will I get in the end?

Will I be able to send email as *** Email address is removed for privacy ***?

Thanks,

Itay.