While it’s true that the US government needs structural reform, the issue wasn’t anything the Constitution can fix by nibbling around the edges. The issue is that the unified Republican elite, along with > 35% of the electorate, is fundamentally lawless and anti-democratic, and will do anything it can to cheat its way into power. All three branches are implicated and have been for a while: Bush v Gore in 2000, the US Attorney firings, Shelby County in 2013, the refusal of the Senate to convict Trump in 2020, the disgusting anti-science politicization of coronavirus, and so on. The scale of Trump’s personal corruption is unique among Republican national figures, particularly in foreign policy. But the racist authoritarianism and fundamental disrespect for elections is a defining creed of the party.
One of the more unpleasant truth about democracy is that it’s quite fragile. In any real sense, the US has only been a democracy since 1965. When large segments of the population are ideologically opposed to democratic governance - universal human rights, respecting fair elections, following the plain text of the law, and so on - mechanisms by which democracy sustains itself begins to fail.
One possibility is to amend the constitution to change first-past-the-post voting in all local-to-federal elections, to let never-Trump types speak out without facing electoral suicide, and to divert right-conservative attention away from a single “leader” figure. And obviously the electoral college needs to go.
But the fact that more than 65 million people voted for Trump at all speaks to a great sickness and nihilism in American culture. Trump himself might be put out to pasture. But Trumpism existed before he got here, and it isn’t going anywhere.