So I was able to setup an IAM user with 2 roles in AWS that allows for separate permissions for my backup and assets buckets. Each role is scoped to that bucket and has specific permissions. I believe that the backup is set to only put and not read or list. Where as the assets bucket is allowing all functions.
However this sounds like an issue with the Backblaze role specification is that correct? Seems like you can only attach a permission to 1 or all buckets and the way that it works with discourse is that they share the same permission keys?