How to reduce long provisioning times for CodeBuild steps in CodePipeline?

We are using CodePipeline to build and deploy our CDK stacks to AWS. However, the pipeline is quite slow and upon investigation we found that the provisioning of a container for the CodeBuild steps were taking between 1.5 - 2 mins and we have 5 CodeBuild steps in our pipeline so the pipeline runs for a long time.

We are using the latest CodeBuild image (aws/codebuild/standard:6.0) and so the provisioning should be quick as the latest image is cached from what I have read.

Are there any other suggestions as to how we can reduce the pipeline execution time?