See post #150 in this thread
I just spoke to AmEx re: the Chubb policy that attaches when you purchase a flight with your AMEX. The rider available on the American Express cc website is the official rider and document - one that can be relied on. I'm satisfied that it provides me with the COVID coverage I need for my...
www.australianfrequentflyer.com.au
Many policies do in fact become void if you are in a country when the advice level changes to "do not travel", which is exactly what happened to me in March 2020. But not all - Medibank for example will still cover you if the advice was not "do not travel" when you arrived at the destination.
I personally think the chances of Australia declaring the US/Hawaii as "do not travel" in the near future are very low. I think you'll be OK.