@NobbZ is suggesting that any back off strategy is not going to produce optimism throughput and may in fact contribute to you getting rate limited messages because you will likely make the “burst” behaviour more prevalent as detected by AWS.
Using a rate limiter will maximise request throughput, create a much more event workload for AWS and therefore reduce the change you get rate limited (according to whatever AWS decides your rate should be).
Using a rate limiter with Elixir (and Phoenix if required) is quite easy. This article might be a good place to start.
