Going through the 241 Castiarina species in iNat, this looks like C. commixta. However there are only 2 observations and they are both near Melbourne. I shaded the beetle for the 3rd shot.
This is definitely Castiarina commixta. It’s an uncommon but spectacular species which I have found in the Blue Mountains near Lithgow as well as further south in the hinterland near Nowra.