Not for the community:

Please delete my Account. I am not receiving any confirmation e-mails on my hide-my-email-icloud-adress.

Probably because Apple Sign in was not correctly configured by your administrators. E-Mail-Accounts from Miro, that send emails to Sign-in-with-Apple-User need to be whitelisted, or those emails will not arrive. I have seen people from 2022 having the same issue…