Does Apple iPad Air 4th generation support Face ID

No. iPad Air4 does not support FaceID.

iPad models that support FaceID have a TrueDepth sensor/camera array - which is not present in any model of iPad that features TouchID.

The TrueDepth sensor incorporates several elements - including an infra-red (IR) dot projector and IR camera.

iPad Air uses Touch ID from the side button, no Face ID.

Absolutely NOT.

The 2020 iPad Air 4 ONLY supports Touch ID via its main power button.

The 2020 iPad Air 4 lacks the needed Face ID camera technology.

Sorry.