You perhaps haven't noticed that all the devices listed in your screenshot have a USB-C connection - unlike your iPad7 that has an Apple Lightning connector. As such you'll not be able to connect a USB-C storage device directly to your existing iPad.
While you can connect many types of external storage devices to your iPad, you will need both an Adapter - and a compatible cable.
You will require an Apple Lightning to USB 3 Camera Adapter - as this provides the ability to connect USB storage devices to your iPad:
https://store.apple.com/uk/xc/product/MK0W2ZM/A
To be recognised by iPadOS, the attached USB storage device must be formatted to FAT, FAT32, exFAT, APFS or HFS+ with a single partition. Microsoft NTFS is not supported. Formatting and partitioning, if required, must be performed using a separate computer; iPad does not provide any facilities to format an external storage device.
Some additional information can be found here:
Connect external devices or servers with Files on iPhone - Apple Support
https://www.imore.com/how-use-external-hard-drives-your-iphone-or-ipad
