I operate my own mail server. I routinely create an email alias for a site when the site asks for my address. This enables me to disable an address that is compromised and/or abused.
I typically end the new address with a hyphen, like this: example-@mydomain.us. When you look carefully at the BNF in the relevant RFCs you'll find that's a legal address.
I subscribed to HaveIBeenPwned on August 9, 2023, using an address with a trailing hypen in the left hand side. I just tried to log in and the Web site's address validation says, "Verification failed! That's not a valid email address."

Multiple email address verifiers, e.g., the one at hunter.io, successfully validate an email of that form.