We’ve talked about OttoFMS managing the retention policy for S3 before and determined that OttoFMS is not the right place to manage that policy. There are a number of tools built specifically for managing lifetimes in S3 locations (including Ottomatic object storage!).
See the conversation on this at the end of this post
You can write a FileMaker file that queries your S3 endpoint, then lets you select files and deletes them, it’s just URL calls
I store on Wasabi and delete things before the 60day minimum retention so that storage does not grow exponentially (and cost)