How to update using iPad data not wifi

iOS/iPadOS updates can only be performed over cellular connections if they are 5G. Apple does not permit device update over other cellular connections.

Otherwise, updates can be performed over WiFi - or using a PC (with iTunes installed) or a Mac computer (with iTunes or Finder - as appropriate for the installed version of macOS) via a direct USB connection with the device.

Unless your device supports a 5G cellular data connection, you don't.

No Apple iOS/iPadOS upgrades/updates can be done over a slower and, possibly, less stable, cellular data connection.

Also, Apple iOS/iPadOS upgrades/updates cannot be done using a WiFi hotspot connection to an iPhone/smart phone cellular data connection, either.

You need to using a stable WiFi Internet connection from a dedicated source, such as a Home WiFi network/Internet connection using a dedidicated MODEM/router system to do ANY wireless Apple iOS/iPadOS upgrades/updates.

Using a slower, less stable, cellular or WiFi connection to a cellular data connection will NOT work!

Best of Luck to You!