There are a few ways you could try to improve your flight experience.
I would recommend you select an extra legroom or exit row seat. This might around 100-200 AUD but I find it makes me feel less packed in and helps me sleep a lot better.
Also, there are paid lounges available too. On Etihad flights, Etihad sells access to their own lounges at Paris, Abu Dhabi and Sydney so every step of the journey, you could access a lounge. This will cost you but if you want more comfort, thats the way to do it. You can see this website for Etihad lounge access for purchase.
On Cathay Pacific Flights, you could buy lounge access at Hong Kong with the Plaza Premium group of lounges. I suggest you book ahead on their website for a cheaper price.
Finally, on the day of travel, ask about paid upgrade offers. Don’t ask for a freee upgrade since you’d almost never suceed. Instead, ask what price would it be to upgrade to Business or Premium Economy. Usually, especially on Etihad, there can be an offer to upgrade to Business for $1000 or so and premium for around half that price.
Keep in mind that you can cancel your flights for a small fee and get your points refunded in full. This is good if you found business class seats later on and want to book it. If you have the points, I’d suggest paying the cancellation fee and booking the business reward outright.
For future flights, it could be worth it to invest in a Priority Pass or a credit card like the Diners Club Premium Card or the Citi Prestige. They give you unlimited free lounge access to lounges around the world which is helpful if you travel economy and don’t have status.