The Logitech Crayon is compatible with all iPaf released from 2018.
According to Wikipedia, the iPad Air 2 was released in 2014.
If these dates are correct, it is not surprising if the Crayon does not work with the iPad.
On my iPad (6th gen., iOS 13.3.2), the Logitech Crayon worked correctly for the most part, but not with a certain app (shapr3D) where the pressure sensitivity of the pen is required. I therefore sold the Crayon again and switched to the Apple Pen.