Take a look at the email service and how emails are exposed (there used to be a backdoor before you implemented instant user account creation). If the "null" email service isn't even accessible anywhere, consider replacing it with a "filesystem" email service, where emails are just written to the filesystem so people can use it safely to have "RestrictedConfirmation" user creation if they want without any hassle or reverse proxies
Take a look at the email service and how emails are exposed (there used to be a backdoor before you implemented instant user account creation). If the "null" email service isn't even accessible anywhere, consider replacing it with a "filesystem" email service, where emails are just written to the filesystem so people can use it safely to have "RestrictedConfirmation" user creation if they want without any hassle or reverse proxies