Yes, Goku could beat just about everything Destiny could throw at him. It would take a very long time though. When he finally gets to the end of the road he runs into 2 problems. Atheon and Oryx. I can't speak for King's Fall as I haven't completed it yet. So how do the guardians defeat Atheon? Their ability to use light as a weapon. Goku also has no knowledge of how the Oracles and the Gorgans work. -The Oracles can destroy him and any recollection of his existance. -The Gorgans can deem his reality false. Thus making him as though he never existed. -He can't use the relic (he can't use light as a weapon) so he has no way to defeat the Templar. -When he gets to Atheon, he can get strewn into the far corners of time. No one is there to help him. (Technically he couldn't even get to Atheon, as he can't use the relic, but shhhh....) I am still chalking this up as a win for Goku seeing as he would have still been able to destroy about 99.99% of everything.