From your post it's not clear that you understand how AWS charges. CloudWatch metrics would only validate your case if these were pay-per-use services like Lamb

From your post it's not clear that you understand how AWS charges. CloudWatch metrics would only validate your case if these were pay-per-use services like Lambdas or something. But you use the word "infrastructure" which implies you have allocated resources and simply don't use them. That's a valid charge. Again maybe you are aware, but it wasn't clear from your post.