THOR wields the MCU’s most powerful weapon and then destroys it, to understand the given statement lets rewind the story and peep into it
THOR-1
He inaugurated when Galactus transformed the god of thunder into his herald due to the impending Black Winter, a threat that has the potential to destroy the entire Marvel Universe and the defeat of this so-called plaque is only possible by powering up Galactus with five hidden planets whose energies will transform the Devourer of Worlds into something even more powerful.
THOR 2
This starts with Galactus consuming the first of these five planets while the unique energies drove the cosmic giant to consume the planet until he annihilated it. The relationship between Thor and Galactus is one filled with hate but driven by necessity and now the return of Beta Ray Bill makes things much more complicated
inference :
Beta Ray Bill comes into existence believing that Thor has fallen under Galactus’ control due to the unbelievable destruction the two have caused, Beta Ray Bill intends to stop them both. However, Thor doesn’t want to be stopped as the fate of the entire universe is at stake. But Bill doesn’t believe him, and he attacks Thor. the only problem is that he is unaware that now he is messing with the Herald of Thunder, imbued with the Power Cosmic, making him more powerful than ever before. The battle between the two continues to be ruthless and after a set of destructive events leads to destroying the Stormbreaker while doing so Thor not only confirms how powerful he is, but he also shows Bill how determined he is in his new quest.