In Apigility has Zend\Mail and Zend\Mime in Api-Tools Skeleton no? How do I send email through Api-Tools?
The current Laminas API Tools skeleton installation is shipped without laminas-mail. You can easily install it with composer. There is a very good documentation on how to send emails with Laminas. Just implement it in your REST resource listener or RPC controller.
If you want to, we can archieve your goal together here in the forum. Just share your code and we 'll put on an example, which can be used by other users with the same issue.