This question was raised quite many times and also, I was in a project where I tried to run Jenkins builder slaves in Fargate. Before this, they ran it in ECS on EC2 instances with the docker.sock mounted.
I tried DinD but with Fargate currently having the maximum storage size of 10 GB I will shut this idea for slaves. We would simply want to be able to cache more data before pruning or recycling the slave. So basically, here the storage size is also a factor when considering to build Docker containers in Fargate