Batch Job Definitions are not able to be deleted, but this blocks the CDK from creating these resources

You're correct that AWS Batch job definitions cannot be immediately deleted and are only permanently deleted after 180 days following deregistration. This creates a challenge when migrating from manually created resources to CDK-managed ones.

Since you can't wait 180 days and can't change the job definition name, you have a few options:

1. Import the existing job definition into your CDK stack using the appropriate import methods. This would allow the CDK to manage the existing resource rather than trying to create a new one.

2. Use a revision strategy. AWS Batch job definitions are versioned with revisions. When you register a job definition with the same name as an existing one, it creates a new revision rather than replacing the old one. You could modify your CDK code to work with this revision system rather than expecting to create a brand new resource.

3. If using the AWS CDK Batch Alpha construct, check if you can configure it to use a specific revision or to update an existing job definition rather than creating a new one.

4. As a last resort, you could temporarily modify your CDK stack to use a different name for the job definition, deploy it, and then update your application to use this new definition. Once the old definition is eventually deleted (after 180 days), you could switch back to the original name if needed.

The key issue is that AWS Batch job definitions are designed to maintain historical versions for tracking and auditing purposes, which is why they can't be immediately deleted.
Sources
How do you clean up old Batch job definitions? | AWS re:Post
Use RegisterJobDefinition with an AWS SDK or CLI - AWS SDK Code Examples
interface JobDefinitionContainer · AWS CDK
Using the Terraform AWS Cloud Control provider for managing AWS Batch resources | AWS HPC Blog