AWS Storage Gateway stored volume gateway is designed for use cases where:

The primary data set remains on premises.

You want to maintain full local access to data with low latency.

You need asynchronous, secure replication and backup to AWS.

With stored volumes, you:

Map gateway storage volumes to local on-premises disks.

Present these volumes as iSCSI block devices to on-prem systems.

Storage Gateway then asynchronously backs up snapshots to Amazon S3, providing secure, durable offsite backup automatically.

Cached volume gateway (Option C) keeps the primary copy in AWS and only a subset cached locally, which does not meet the requirement to maintain full local access to all data.

Snowball and Snowball Edge (Options A and B) are primarily for bulk, one-time or periodic offline data transfer and do not provide an ongoing backup solution with continuous local access.