This enclosure uses a (variant of) JMicron JMB39X, which has (unfortunately) a rather peculiar implementation of ATA passthrough -- see also https://www.smartmontools.org/ticket/705 .
I will look into this and see what I can do.
I have some internal projects related to implementing RAID support into opensea-transport so I can make this a subtask for project.
This enclosure uses a (variant of) JMicron JMB39X, which has (unfortunately) a rather peculiar implementation of ATA passthrough -- see also https://www.smartmontools.org/ticket/705 .