Creating new Apple ID/ email address without losing the mail in existing email account
My iCloud email address, which is my Apple ID, was hacked in a medical provider data breach. I've been getting dozens of scam emails every day since. I know how to block specific addresses and have constructed Rules to delete emails, but have had some of the same problems as others in getting Rules to work proactively. So I want to change my iCloud address and use it as my new Apple ID. I wish to do this without losing all of the mail I have stored under my existing email address. I have read a lot on line about this, but am having trouble understanding the exact sequence of steps I should take. Any help in doing this (new iCloud email address/Apple ID and transfer of mail from old email address to new) would be appreciated.
Mac Pro (2019)

