How do I remove and reuse Apple primary email address for mail aliases?

Re: "Is it possible to remove my Apple primary email address and then reuse- "

No. The primary email address can be used to log-in to iCloud, your devices, and your Apple Account.

Apple support's online article: Create a primary email address for iCloud Mail - Apple Support

Eg: says:

"Note: You can’t rename your primary iCloud Mail email address later.

If you change your mind, you can add an email alias instead"

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Re: " ... mail aliases ..."

Add and manage email aliases for iCloud Mail on iCloud.com - Apple Support

Eg: says:

"After you set up a primary iCloud Mail address, you can create up to three @icloud.com email aliases on iCloud.com. After you set up an alias, you can send and receive mail from that alias on iCloud.com and on any device that has Mail turned on in iCloud settings."

and

"Note: If you have three email aliases and you delete one, you must wait 7 days before you can create a new one."