Is there a service that lets me send mail from such an email address as well?

Let's say I use this for my Amazon account amzn.myusername@mailhero.io and I need to get in touch with Amazon customer support. For verification they require me to actually send an email from amzn.myusername@mailhero.io.

Or another case: as soon as I have to actually send an email to a service I signed up for and use my real email address, that is then known to the service and could potentially be leaked.