Enable/Disable USB device on a schedule

I have a Seagate Backup Plus 5TB external HD conntected to my PC via USB. The external HD is only used for weekly backups. It is the loudest component of my PC. I don't want to listen to the HD spinning up, which happens frequently from what I can only assume to be background Windows processes.

I currently have the external HD disabled through Device Manager. I manually enable it on Sunday evening before going to bed so that the scheduled backup can write to it over night. I disable the external HD again in the morning so it will remain silent. I would like to be able to schedule the device to automatically enable/disable before/after the scheduled backups. This will ensure the backups happen even if I forget to manually enable the device.

I have tried to figure out a way to do this using Task Scheduler, but didn't see how I could set this up as a task. I have also tried creating two batch files (one to enable, one to disable) that would change the Start value in the USBSTOR registry key but I could not get this to work successfully. When I ran the batch file to disable USB storage I was still able to see and access the external HD (I confirmed that the Start value did change to a 4 which is supposed to disable, so not sure what I did wrong here). The plan was to set up the batch files to execute using Task Scheduler. Not sure if that would have worked anyway, as the batch files need to be run as administrator.

Does anyone have any suggestions? Is there any freeware available that would allow for a scheduled enable/disable of a USB device? Appreciate any help you can offer. Thanks in advance.