I think probably the best way is create a button on that section for example Account Deletion Request clicking on this button a PM (admin is the recipient) composer opens with some placeholder (title and textarea). This way users easily can send an account deletion or anonimazition request and Admins also can review the account before delete or anonimize it.
This button would appears when canDeleteAccount is false (so the default Delete My Account is not appears) or make it trust level restriction and it can use the user-preferences-account plugin outlet which is here on account page. But the better position is on the bottom of the page. Just like where the default button is appear.
If I have some time maybe I create a theme component for this. 