iPad Air 4 screen unresponsive after IOS15 update

If it is new, there is a a chance it is a hardware problem.

Please check out this website: https://support.apple.com/en-us/HT201406

If purchased from Apple, if that iPad is still within the 14-day unconditinal return policy, return this device to your local Apple Store and get another new device.

If you can, spend some time in the store and setup the device to make sure this issue isn’t happening with another new device.

You need to search online for your nearest, “local” Apple store location and call contact phone numbers and call to make an appointment to have your Apple iPad returned under the 14-day return period and get another new device and test it in the store before leaving.

Best of Luck to You!