The missing piece of the "multipolar" assumption is whether there's any real trajectory for deglobalisation. I think that remains to be seen and the question is being tested now.
The utility of military power will mostly be at flashpoints in the imperial peripheries like Palestine or Ukraine (not at all discounting the people who live in these "peripheries", but it's their geography that allows empires to view them as expendable) while China and the US remain interdependent.
The self-preservation trick for imperial satellites like Australia is not to think like an imperial periphery. It's when your country ends up as little more than a subsidised missile and submarine base that you're in real trouble.