To me, it kind of sounds like a bastardized version of “English (UK)” with a Boston accent attached to it plus bizarre slang and strange spelling of some words (I.e. gaol is pronounced as “jail” I know, WTF? As I’ve thought they’re trying to spell goal).
The weirdest part are the different meanings of words that are spelled the same (I.e. “Thong” is defined as a swimsuit underwear in American English but from English AU, it’s flip flops) along with “C*NT” being part of their vernacular.
I feel like I’m witnessing a cliche here; an American discovering that other countries exist. Wait until they realise America isn’t the centre of the universe.
I get that it’s fun to dunk on Americans, but considering OP is asking whether AU english sounds weird to American ears, I would assume they do not themselves have American ears, or the question would be unnecessary.
Reads to me like they are the “American ears” they are referring to, as if their world view is the default rather than the bias of an individual.