Meanwhile I am a happy user of :ex_aws or :req_s3 which has done everything I need it to do. Object ops, iam policies, etc. A dependable S3 client has been there for years. The elixir core team doesn't need to maintain it. ReqS3 is one of my favorite things to use: https://hexdocs.pm/req_s3/readme.html

Maybe you can guarantee Phoenix will be maintained 5-10 years from now but that's really not the case for some random library on Github.

If you look around you'll see this kind of stuff is really one of the biggest blockers for Elxir and Phoenix. Especially for something as fundamental as cloud storage.