Synology integration trigger by unmount usb to switch wifi power plug

What I did,…
On my synology Installed USB/SD Copy, and configured it so it makes a backup the moment the USB is plugged in (activated) and unmounted/removed when the backup is finished.
I connected the external HDD with a Wifi power plug so that I can turn it completely off when the backup is completed.

What I want:
I would like to automate that HA switches off the power plug/HDD when the USB is unmounted/removed. (and not when the backup is not finished)

I added the Synology integration to HA. But I don’t see the USB as an entity, so can’t monitor the status. Which is needed to make the automation possible.

Is there a solution to make this possible?