not able to get port 25 for lightsail server !

By default, AWS blocks outbound traffic on port 25 (SMTP) on all Lightsail instances and other AWS resources like EC2 instances and Lambda functions. This is a standard security measure implemented to prevent potential spam and abuse, not specifically to force customers to use paid email services.

You have several options to address this:

1. Request removal of the port 25 restriction: You can submit a request to AWS Support using the "Request to remove email sending limitations" form. You'll need to provide details about why you need port 25 opened and how you'll prevent spam/abuse. The approval process can take up to 48 hours, and AWS may deny requests, especially for testing purposes. Refer https://docs.aws.amazon.com/lightsail/latest/userguide/amazon-lightsail-configuring-reverse-dns.html

2. Use alternative ports: Consider using ports 587 (TLS) or 465 (SSL) for SMTP connections, which are generally more secure and don't require special permission from AWS.

3. Use Amazon Simple Email Service (SES): This is AWS's email sending service designed specifically for sending emails from AWS resources.

4. Use a third-party email relay service: Many email providers support sending through alternative ports.

While I understand your frustration, this restriction is primarily a security measure implemented across AWS services to prevent email abuse, rather than an anti-competitive practice. Many cloud providers implement similar restrictions on port 25 to combat spam.
Sources
SMTP issue, not able to send out Email through the port | AWS re:Post
Host websites, email, and services with cPanel & WHM on Lightsail - Amazon Lightsail
how to open port 25 in cloudshell | AWS re:Post
SMTP Limitation | AWS re:Post