
Maybe I’m biased bc I’m American and not Australian but unless you’re American faking a different kind of American accent nobody is good at doing a fake American accent even as a parody. Like even when it isn’t supposed to be believable it’s just for a joke ppl cannot manage to sound American. The R is difficult bc our R pronunciation is fairly rare. But also like, the roundness of vowels and the lexicon itself.
I think Australian has more of a niche sound to it - a lot of people around the world watch American media so the accent is more accessible to recreate. But, for example, I once saw a creator from New Zealand make fun of someone for mistaking a New Zealand accent for an Australian one (to them the difference was clearly obvious) and I can’t hear the difference at all