If anything, those four years showed how poorly the system holds up against bad actors simultaneously in all branches. I'm not sure how you can solve that, though.
Corruption is a rot, slow, like a corpse decomposing. It's an ongoing process that is only opposed by daily actions of cleaning off barnacles. America collected a lot of barnacles from those four years, and the rate at which they've been purged is probably too low. The recent spate of anti-voter laws and gerrymandered districts just shows the steal is ongoing.
I am reminded by Julius Caesar, who, unlike Donald Trump, was smart and competent. Caesar pushed against institutional democracy in Rome (such as it was) and found that very little pushed back.
Gaius didn't destroy the republic, he just wanted to be the one to step up to the throne of its shambline corpse. And it would have worked, if not for those meddling... senators.