What myth are you talking about?
On the day of the formal process of certification, January 6, 2021, did Donald Trump falsely insist to a crowd of supporters in front of the White House, that his Vice President had the power to cast aside electoral college votes from states they had mutually lost in the 2020 Presidential General Election? Yes, he did.
Did Trump's false insistence instill an incorrect belief in his crowd of supporters that he could still retain the presidency? Yes, it did.
Did Trump encourage his crowd of supporters to march down to the Capitol? Yes, he did.
Did this crowd of supporters go down to the Capitol merely to protest the outcome of the 2020 Presidential Election, or did they march down to the Capitol to disrupt the proceedings, under the belief that Trump could still retain the presidency if they took this action? Under direction from Donald Trump, who had made the rally happen, members of that crowd marched down to the Capitol to disrupt the formal certification of the electoral college vote, because they falsely believed that Trump would retain the office of the presidency if they did.
Donald Trump attempted to prevent a transition of power, in the United States federal government from occurring. Trump incited a riot. NOTHING has been disproven about that.