It's a mixed bag. Having moved to Canada, even modern constitutions can be a shitshow. For example, Canada's constitution allows premiers (the Canadian provincial version of state governors) to freeze certain rights from Canada's version of the Bill of Rights (the Canadian Charter of Rights and Freedoms) on a whim until the next election. Ontario's premier, Doug Ford, recently tried to use this technicality to freeze the right to protest to stop a school workers' strike.

The reason this ability exists is because when Canada first became an independent nation and created its constitution (in the 1980's), the provinces would only sign onto it if these kinds of exemptions to their Charter of Rights and Freedoms were included. Looking at it from that perspective, the strength of the Bill of Rights actually looks pretty impressive by comparison.

The other factor I think is worth considering is that when it comes to the legitimacy of constitutions and governments, time is everything. When you reach around the age of a century old, the mere fact that your country had made it that long with that constitution starts to lend legitimacy and stability to it. Which is to say that if we had a brand spanking new constitution, everybody would be questioning it. Worst case scenario you get civil wars. Slightly better, but still bad scenario is a lot of disillusioned people that refuse to abide by the new document. America's constitution is old enough that it gets a lot of respect from even the most fierce of rivals. That's pretty invaluable, especially in times of political turmoil.

I believe that Trump would have had an easier time trampling over a newer constitution, regardless of how well thought out the document was. Having a constitution steeped in a national mythology and at the center of so many norms and traditions protects us from even some of the worst stress tests. The greater challenge isn't a crazy stress test like Trump, but the gradual decay of those norms. Which is to say that I really believe our norms have been protecting us even still, after so many things have been thrown out the window lately. Creating a new baby constitution in the midst of this messy era of politics would be one of the worst moves we could make.