Clovis first has been, at best, a hypothesis. It’s devilishly hard to prove anything through the absence of contradictory evidence. I’ve always had a rule of thumb that anything will prove to be more complicated than is first thought. Incontestable conclusions are usually the product of tenured professors guarding their turf.
People were able to get to Australia some sixty thousand years ago at least. The lower sea levels through the various ice ages including the recent hypothesis on Beringia leave a lot of room for speculation. DNA studies would seem to limit the European influences, however.
The settlement of Australia is a particularly hilarious example, imo, of the landlubber mindset at work — Flores Island was not connected to the mainland, even during glaciation, during the generally accepted time of hominim settlement of the Earth, and yet, there are tools on the island dating to 800,000 years ago. IOW, someone earlier than us decided as a one-off to go boating, ended up on Flores, and no one followed or left the place thereafter. Then, 740,000 years went by and boats were again invented by someone as a one-off, and they colonized Australia, never to leave again. Another 59,000 years passed and, during the Age of Sail, someone from outside discovered Australia. :’)
Hrdlicka’s view was that the Americas were first settled 3000 years ago, and until radiometric dating came along after WWII, that was still being pushed as reality — but the 3000 year floor gave way to another arbitrary floor, for no reason whatsoever.
A similar problem existed in Japan — a late settlement date was the accepted view, and when excavations of possible prehistoric human sites hit stuff of the right date, no one bothered to continue to dig.