With the upcoming iPadOS, you'll be able to plug external drives and SD cards into your iPad the way you already can with your Mac or Windows PC.
IPadOS - Drives - Users - USB - Drives
"iPadOS ... supports external drives, allowing users to easily plug in USB drives, SD cards or log into an SMB file server, all from within the Files app," Apple said in a statement Monday at its Worldwide Developer Conference, aka WWDC, in San Jose, California.
The new feature reflects how much closer iPads and Macs are becoming. iPads...