Some of the AWS built-in roles are an absolute car crash, no idea how they got through review (EMR is a good example). I use the built-in roles by default, but only after thoroughly reviewing the policies, I create my own based on that if I find anything I don’t like.

It’s not restricting amazon’s access that I’m worried about, more privilege escalation (e.g non-constrained iam:PassRole in combination with anything is a good one)