It is not possible, the 1 tb Seagate hardrive has no operating system & has no app in the App Store.
You can transfer to your pc and then from the pc to the 1 tb Seagate hardrive, see -> Transfer photos and videos from your iPhone or iPad to your Mac or PC
Transfer photos and videos from your iPhone or iPad to your Mac or PC - Apple Support
or
You can use a SanDisk iXpand flash drive to use as an external hard drive. They are available in various sizes.
You can also use that iXpand flash drive as a tool to save the photos to a real external hard drive afterwards.
iXpand Flash Drive are available at Apple Store and at Apple Authorized Service Providers.
iXpand flash drive app can be downloaded from the App Store.
See -> SanDisk iXpand-flashdrive Go -> SanDisk 64 GB iXpand Flash Drive Go - Apple
Then download the SanDisk iXpand Drive app from the App Store, see ->
https://apps.apple.com/us/app/sandisk-ixpand-drive/id1079870681