In theory, SSD storage can be connected to iPad and iPad Pro with caveats…
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.
As the iPad has limited power capabilities, dependent upon the Storage Device, an external power source is often required.
If you have one of the newest iPad Pro models, with a USB-C connector, you may need to utilise a powered USB hub (i.e., it has its own source of power) - connecting both the iPad Pro and the storage device to ports on the hub. iPad models with a Lightning port will require use of an Apple Lightning to USB3 Camera Adapter:
- Lightning to USB 3 Camera Adapter
https://store.apple.com/uk/xc/product/MK0W2ZM/A
When using external USB/SSD storage, you will almost certainly require connection to an iPad Power Adapter rated at 12W or greater. The Lightning to USB3 Camera Adapter has a pass-though Lightning port specifically for connection of the iPad Power Adapter.
Some additional information about connecting external storage solutions 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
