There isn’t a ban on all Australian beef. Trump thinks it is unfair we still ban US beef after 22 years. A half decent PM who had a relationship with the US President would be able to negotiate tariff free access simply by allowing US beef into the country. Realistically, most of the countries which banned US beef back then have already allowed access again. The low Aussie dollar and shortage of US beef means very little product would ever get here but it would be a show of goodwill.