Not familiar with this particular library, but similar libraries use S3 Express One Zone which has write latency <10ms, so you can use that for the WAL and compaction can move data onto other storage classes in the background.
Regular S3 has write latency 100-150ms, which might be fine depending on your workload anyway.
Regular S3 has write latency 100-150ms, which might be fine depending on your workload anyway.