Apparently they also found Chinese coins https://www.australiangeographic.com.au/news/2014/08/18th-ce...
Personally, having studied Chinese history, travelled the area fairly extensively, and read all of the Ming Dynasty texts around Zheng He's voyages (~1400s), I am sort of convinced it would have been unthinkable for the Chinese not to have visited northern Australia, since (a) presence of land should have been well known / established through local knowledge, currents, clouds, winds, and seabird migrations; (b) they went to so many other places, it seems insane they would stop just after the equator when they already had compass-aided navigation and strong (for the period) navigational astronomy. Still, stranger things have happened...