Opening Port 25 for web server

I am hoping someone can help me. I am building a test environment for a client who wants to launch an EC2 instance with the Plesk control panel. The site will be used to host websites and web services for my client.

The site needs to send email notifications to my client and his users. There will not be a public email server, email for the domain is handled at Google Workplace. I manage Plesk servers and understand how to lock them down to prevent relays, and there will be no emails generated from user input.

I understand that Port 25 is blocked. I have send three requests using the form at https://support.console.aws.amazon.com/support/contacts#/rdns-limits but have not heard back. Is there something else I need to do?