@jhallettbc , this is exactly my case! I had F-mount 14-24 and I even took it with me to Africa many times! But it was big and heavy. Meanwhile I have two Z-cameras and sold my F-mount. And I am thinking about Z-mount 14-24 for about 1 year already. Actually, I sold F-mount becasue of it. But still cannot decide to buy Z-mount.
At the moment I use 24/1,4 Sigma and 18/2.8 Zeiss Batis ...
This year I planned some spots in Africa where I have an excellent nightscape opportunity! I used 14-24 primarely for nightscapes.
You told you are going to Australia! How good it is for nightscapes! Do you know a youtube channel "Nightscape Images" from Richard Tati? It is quite a famous channel and he is living in Australia, he is talking also about good locations. I'd recommend to have a look!
And please, please, post your images and make a review about z14-24 for nightscapes and astrophotograpohy when you are back!