Any experience with reducing costs when migrating to aws lambdas?

Answer 1

Create your AMI in a single account, then copy it to further regions and share it with other accounts. You will now have an identical, unencrypted picture across your surroundings. Copy the AMI, and then use your preferred local key to encrypt it.

Source : https://www.sevenmentor.com/amazon-web-services-training-institute-in-pune.php