Create a custom Docker image containing all dependencies for the legacy application, store this image in a new Amazon Elastic Container Registry (Amazon ECR) repository, and configure an AWS CodeBuild project to use this Docker image for building the deployable artifact, saving it to the S3 bucket.

Launch a new Amazon EC2 instance, install all necessary dependencies for the legacy application on this instance, and use it to build the deployable artifact, saving it to the S3 bucket.

Create a custom EC2 Image Builder image, install all dependencies for the legacy application on this image, launch a new Amazon EC2 instance from it, and use this instance to build the deployable artifact, saving it to the S3 bucket.

Create an Amazon Elastic Kubernetes Service (Amazon EKS) cluster with an AWS Fargate profile running in multiple Availability Zones, create a custom Docker image containing all dependencies for the legacy application, store this image in a new Amazon Elastic Container Registry (Amazon ECR) repository, and use this Docker image within the EKS cluster to build the deployable artifact, saving it to the S3 bucket.