Build docker image on fargate Jenkins agent

Question

I have deployed an ECS fargate Jenkins cluster similar to this solution https://aws.amazon.com/blogs/devops/building-a-serverless-jenkins-environment-on-aws-fargate/

There will be two kind of piplelines running

1. Building application docker Images
2. Everything else e.g. infra deploy etc.

For option 1 above i.e. building application docker Image, its docker in docker situation. I know using Kaniko is an option but it gets very complicated.

So I tried following plugins instead so that I can use alternate options/agents to build docker images and avoid docker in docker situation.

1. EC2 ephemeral agent plugin
2. Codebuild Plugin
3. Codebuilder plugin

They all work fine and satisfy my requirement but they all require using AWS Access Keys in Jenkins Credentials, which kind of is an anti-pattern and customer I am deploying this solution for might not accept putting IAM User access keys in Jenkins. IAM roles instead of AWS access keys can't be used as Jenkins Controller is a fargate container. Not sure, what to do in this situation.

Any help to solve this conundrum will be much appreciated.