S3-compatible interface fails miserably

Object Mount, MountainDuck and rclone mount: rclone mount storj:my-bucket z:\ --vfs-cache-mode full --no-console

or just

rclone copy -P x:\VM storj:my-bucket

It will not need any cache and will transfer everything in a background in several streams, so it would work faster.

Then you likely need to use a normal backup tools, which also support snapshots, like Duplicacy or restic and others. Almost all has an own web-GUI and standalone GUIs, or you may use something like Duplicati. If you backup VMWare VMs, then it’s better to use Veeam.