Dragon Ball Super has seen its fair share of villains, including a God of Destruction who sought out Goku for a fight, an evil space emperor who escaped Hell to exact revenge on Goku, and a disgruntled Kai who met Goku and decided to steal his body and use it to purge all life from the cosmos. There was even, at Goku's request, a multi-universe tournament in which losing universes were destroyed. Looking back, it's clear that, during its 131-episode run, Dragon Ball Super has only had one villain the entire time: Goku.
At the end of the Cell Saga in Dragon Ball Z, Goku sacrifices his life to save the world but opts to remain dead rather than be revived by the Dragon Balls. He wisely notes that he is indirectly responsible for the recent string of attacks on the Earth. Dragon Ball Super has featured significantly higher stakes, with the universe and even multiverse being in constant danger. This time around, Goku is directly responsible for most of these threats with his selfish obsession with finding strong opponents. Worse, Goku has not been able to resolve any of the problems he causes, consistently being bailed out by someone else.
The initial encounter with Lord Beerus, Universe Seven's God of Destruction, is one of only two conflicts in Dragon Ball Super that Goku is not directly responsible for. Beerus has a vision of battling a Super Saiyan God and seeks out Goku, as he is known to be the strongest remaining Saiyan. So, while this conflict cannot be blamed on the mighty Saiyan, it was the first instance of Goku's enemy magnetism and the issue needing to be resolved outside of battle. In this case, Beerus easily defeats Goku but opts not to destroy the planet because he likes the food.
Frieza's return from Hell to take his revenge on Goku is the kind of thing that he stayed dead to prevent from happening in DBZ. Frieza's subsequent destruction of Earth is indisputably a result of Goku's pathological need for a sparring partner. His repeated attempts to allow Frieza to retreat so that he can come back even stronger only result in the villain destroying the entire planet. Goku had easily overpowered him yet refused to finish the job. If Whis had not been present to turn back time, the Earth would have been lost forever, thanks to Goku.
The Tournament of Destroyers between Universe Six and Seven was not Goku's idea, but his irresponsible approach to the final showdown still manages to land the Earth in hot water. As Universe Seven's second to last fighter, facing off against Hit, Universe Six's last fighter, Goku had the opportunity to win the battle and save the day. However, he forfeits his match against Hit as a show of honor for a good fight, putting the Earth in danger of being transported to Universe Six by the Super Dragon Balls. If Hit had not likewise forfeited his following match against Monaka, the Earth would have been doomed by Goku once more.
When Future Trunks makes his return, he brings news of an evil version of Goku that has laid waste to his timeline. Dubbed Goku Black, the villain from the future is revealed to be none other than Zamasu, the Supreme-Kai-in-training from Universe 10. Goku insists on joining Whis and Beerus as they investigate the present-day Zamasu, whom Goku annoys into sparring with him. This encounter with Goku is what gives Zamasu the idea to steal Goku's body and emboldens him to enact Project Zero Mortals. Once again, Goku's desire for a fight backfires on a cosmic scale, this time dooming an entire timeline. When Goku was, for the fourth time in as many arcs, unable to defeat the villain and had to call on Zeno, the supreme ruler of all creation, to solve the problem for him.
Last, but not least, Goku is solely to blame for the Tournament of Power, which resulted in the, albeit temporary, destruction of seven other universes. Even though the elimination of the losing universes wasn't Goku's idea, it never would have happened if he hadn't reminded Zeno in the first place, as the child-king of reality had completely forgotten about the tournament. Goku had been warned profusely about the Omni-King's penchant for pointless destruction and should have known better than to remind him about, well, anything. And yes, still, Goku has to rely on someone else to clean up the mess he's made, getting bailed out one last time by Android 17's wish to resurrect the destroyed universes.
Dragon Ball Super has transformed Goku from the savior of the universe to a thoughtless harbinger of death and destruction. While he always stands between the villains he creates and their evil goals, he rarely does so for altruistic reasons. Generally, he's just excited he has a new, powerful opponent. He even goes as far as admitting that he's just interested in fighting tougher enemies, and saving the world is just a side effect. If a person is deemed a villain based on how many times they endanger the entire universe and force someone else to save it, then Goku is the most villainous character in Dragon Ball Super, and it's not even close.