After wresting with the very basics of AWS accounts I've started https://practical.li/blog-staging/posts/access-aws-with-clojure-from-scratch/, using the Cognitect Labs AWS API. The Clojure library is wonderful to use and I'd highly recommend it. I'll fill out the article either tonight or tomorrow morning and hopefully people can advise on a more secure way to use AWS - without using an SSO service (or using one that has a free tier)