iPad air 4th gen screen lifting and bent

You might be best advised to your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to assess your iPad - and you can explore your available options:

Genius Bar Reservation and Apple Support Options - Apple

Alternatively, you might consider Apple's mail-in repair service. You can verify both eligibility and cost for your region/country here:

iPad Repair & Service - Apple Support

For practical purposes, in lieu of repairing and returning your own iPad, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. If you have benefit of an active AppleCare+ plan, the cost of repair is reduced to a small excess/deductible fee.