Deleting of Listener or a Target Group

Regarding your technical question about deleting unused listeners or target groups:

Yes, you can safely delete unused listeners or target groups associated with your load balancer, as long as they are not being referenced by any active components.

For listeners: You can delete a listener if it's no longer needed. The process involves using either the AWS Management Console or the AWS CLI. When using the console, you would navigate to the EC2 dashboard, select your load balancer, go to the Listeners tab, choose the listener you want to remove, and then use the Actions menu to delete it. You'll need to confirm the deletion by typing "confirm".

For target groups: You can delete a target group if it is not referenced by any listener rules. It's important to note that deleting a target group does not affect the targets (such as EC2 instances) registered with that group. If you have EC2 instances you no longer need after deleting a target group, you can stop or terminate them separately.

Before deleting either listeners or target groups, ensure that:

1. They are not being used by any active components of your application.
2. Removing them won't disrupt your current traffic flow or application functionality.
3. You have confirmed that the remaining listener (Port 443) and target group (Port 80 or 8080) are correctly configured to handle all your required traffic.

As always, it's a good practice to double-check your configuration after making changes to ensure your load balancer is still functioning as expected.

Sources
Delete a target group for your Network Load Balancer - Elastic Load Balancing
DeleteListener - Elastic Load Balancing
Delete a listener for your Network Load Balancer - Elastic Load Balancing