There is no official or unofficial consensus from Apple about re-using an email address. When people ask if you can re-use an email address for an Apple ID, Apple at times agrees with contributors on the forum saying you can, and at other times those saying you cannot. Officially we don't know but empirical observations suggest no.
"If you see a message that the email address you want to use isn't available or is already in use, check that you or a family member aren't already using that email address with a different Apple ID. If a family member is using that email address, remove it from their account then try to use it." From: https://support.apple.com/HT202667
Apart from the above statement I have yet to find a formal Apple position statement online about re-using email addresses. Many user reports on this forum (given the large number over many years I don't have specific reason not to believe them) suggest that contrary to what the statement implies as to ease of address re-use, if you have recently used an email address with Apple for another purpose such as a notification email address it cannot be re-used; at least not immediately and possibly never. I guess you can "try to use it" but for many this does not work. Apparently even the official Apple Support team is inconsistent as to position about re-using email addresses:
Here is an April 2021 post by ASC contributor IdrisSeabright that was recommended () by an Apple Recommended team member - "Once you've used an email address as an Apple ID, it can't be used again for an Apple ID, even if the first Apple ID has been deleted."
https://discussions.apple.com/thread/252629414?answerId=255095641022#255095641022
This Community Specialist makes a similar statement to be above: "When you go through deleting an Apple ID, it cannot be used again as an Apple ID"
https://discussions.apple.com/thread/253338991
In complete contradiction, another Apple Recommended team member favored -- over a reply referring to the recommended response in a previous paragraph saying you cannot re-use an email address -- a Sept. 2021 post saying just re-use an old email address: https://discussions.apple.com/thread/253165777
'Anecdotal' posts:
April 2021 post https://discussions.apple.com/thread/252629414
- Original post: "I tried contacting chat support and finally phone support today and they told me that you can NEVER use an email address that was used for a deleted account."
October 2021 post https://discussions.apple.com/thread/253209773
"I deleted the second Apple ID and waited 30 days for the deletion process. Tried to change the email of her initial Apple ID to her current email address, which she can access but it says; 'This email is not available'."
