There is evidence to suggest that Donald Trump's rhetoric and false claims about the legitimacy of the 2020 presidential election contributed to the attack on the US Capitol Building on January 6, 2021. Trump had repeatedly claimed, without evidence, that the election was "stolen" from him and that there was widespread fraud.
In the weeks leading up to the attack, Trump held multiple rallies where he encouraged his supporters to "fight" and "never give up" in their efforts to overturn the election results. On the day of the attack, Trump addressed a rally of his supporters near the White House, where he continued to baselessly claim that the election had been "rigged" against him.
After the rally, his supporters marched to the Capitol Building, where they breached security and ransacked the building. The rioters chanted pro-Trump slogans and carried Trump flags and merchandise. Five people, including a Capitol police officer, died as a result of the violence.
It is important to note, however, that while Trump's rhetoric may have contributed to the attack, he did not directly incite it. In his speech at the rally, he told his supporters to march peacefully to the Capitol.
As for the second part of the question, there is no concrete evidence to suggest that Trump wants to become a dictator with supreme power over the United States. However, many of his actions and statements during his presidency, including his attacks on the media and his attempts to undermine the legitimacy of the judicial system, have been perceived as authoritarian by some critics. Ultimately, only time will tell what Trump's true intentions and aspirations are.