why won’t my apple pencil gen 2 connect to my a ipad air 3

Only the first generation Apple Pencil can pair with the iPad Air 3.

Apple Pencil compatibility - Apple Support

Yup,

You purchased the wrong version Pencil.

You need to purchase the 1st gen Pencil with the silver, chrome top with magnetic Lightning connector protective cap.

Return the Pencil 2 from where you purchased and purchase the 1st gen Pencil, instead.

It might not be compatible with Air 3

So u wasted AUD 199