The only option left to you is to escalate this issue.
However, you need to realise that proving a cracked screen is a manufacturing defect and NOT some fault of its users,is going to be be extremely, if not virtually, impossible to prove.
If you did not purchase extended, two-year+ AppleCare+ for this expensive iPad, then if you cannot prove a manufacturing defect/issues with iPad Air 4 touch screens, then I am afraid that a replacement device is going to be expensive to purchase.
You need to contact Apple support via the contact support link located at the upper right hand corner of every Webpage of these Apple support communities.
Use the Hardware Repair support category.
OR
by installing and using the Apple Support app found in the iOS App Store.
Tap the iOS App Store link below.
https://apps.apple.com/us/app/apple-support/id1130498044
OR
Call contact Apple via the support numbers found in the link bekow.
Contact - How to Contact Us - Apple
Tap the link below.
https://www.apple.com/contact/
Best of Luck to You!