connecting a usb c cable to a lightning cable

It truly is false economy to attempt to extend a USB-C to USB-C cable, using an adapter, to join a presumed USB Type-A to Lightning cable - when the correct cable (that will work as intended) is readily available:

• USB-C to Lightning Cable (2m)

https://store.apple.com/uk/xc/product/MQGH2ZM/A

What do you hope to achieve by interconnecting two iPads directly by way of a USB cable?

In general, if you need a longer cable, you would be best advised to simply acquire the correct cable for the purpose. Longer cables, when used for charging, need heavier gauge wiring than shorter cables. Otherwise the electrical resistance of the individual conductors will lead to significant voltage drop - and may even prevent reliable charging. USB standards also generally preclude the use of simple cable adapters - as cable adapters can potentially introduce incorrect wiring combinations that can lead to damage.

When compared with the very high cost of repairing a damaged USB connection of an iPad, the cost of simply purchasing the correct cable for the job recedes to insignificance.

To repeat my question, what do you hope to achieve by interconnecting two iPads directly by way of a USB cable? Unless you intend to share the Cellular hotspot of an iPad, or attempt to charge an iPhone or older iPad from a 2021 model iPad Pro, a direct wired connection will serve no purpose.

If intending to make a direct connection, unless you use a single cable, there is no guarantee that the connection will function at all.