If your iPad is running 14.3 you CAN purchase potable USB-C SSDs ( Solid State Drives -no moving electro-mechnical parts ) that can be used with your iPad.
SanDisk and Samsung are the most popular SSDs for iPads. You can find these on Amazon in different storage sizes for different price point.
To use these types of portable drives, you need to have the iPad connected to its charging source using this Apple Adapter.
https://www.apple.com/shop/product/MK0W2AM/A/lightning-to-usb-3-camera-adapter
You plug your iPad's power/charging cable into this adapter and to your plugged in Apple power/charge block, and the USB-C SSD into the USB-A connection, on the adapter, using the proper cable supplied with the SSD.
Most of these portable USB-C SSDs will come with a myriad of cables.
One of which will be a USB-C to USB-A cable.
To use the SSD with your iPad, first it needs to be re-formatted using a Mac computer ( for this part, if you have any friends or family that have a Mac, you could see if they can help you with getting this SDD formatted properly, if you do not own a computer )
OR,
Locate and call contact your nearest, “local” Apple Store location and make an appointment for them to format this drive for you to get to to work with your iPad model.
The drive needs to be formatted in Apple Mac native computer format, APFS, FAT32 or ExFAT to work with an iPad.
Once the SSD is formatted properly and your iPad properly powered, when the SSD is plugged into the iPad it will appear in the iOS/iPadOS Files app.
When it appears, you can transfer just about any data back and forth through this app and the data should be able to be opened by the iPad, once the data is transferred.
Also, the iPad should be able to see and read data direct from this drive, also.
You do not necessarily need your own computer, but it would be better to own one as they are more powerful than any iPad and this would be a good place to do iPad data backups, and to do device restore/recover if your iPad ever crashes as a Mac or Windows PC is needed to do this.
Here are examples of the SSDs I am referring to.
https://www.amazon.com/SanDisk-2TB-Extreme-Portable-SDSSDE61-2T00-G25/dp/B078STRHBX/ref=sr_1_2_sspa
https://www.amazon.com/Samsung-500GB-Portable-Solid-State/dp/B074WZJ4MF/ref=sr_1_3
https://www.amazon.com/Samsung-T5-Portable-SSD-MU-PA1T0B/dp/B073H552FJ/ref=https://www.amazon.com/Samsung-T5-Portable-SSD-MU-PA1T0B/dp/B073H552FJ/22d05c05-1231-4126-b7c4-3e7a9c0027d0&th=1
As you own an iPad with Apple's proprietary Lightning connector/port, do not expect the fast transfer speeds of these portable drives as the Lightning connector /port speed is much slower than that of a USB-C connector equipped iPad, but these drives DO work with Lightning connector equipped iPads and using an external power source such as Apple's 12W power/charging adapter or greater.
You will always need to use the added Apple USB-3 adapter and external power source to use ANY external drives with iPads equipped with Apple's own Lightning connector/port.
So keep that info in mind.
