Jefferson Davis, of all people, was never tried. Congress voted that he should be tried for treason by a military court, but he was never put on trial.
Interestingly for our topic of discussion, Davis' attorneys argued his disqualification for office under the 14th was his punishment, and further charges would be double jeopardy. Note that they argued Davis was disqualified without having been tried and convicted of anything. There's an argument Trump's lawyers should have tried, accept the Insurrection Clause and argue double jeopardy in the DC case! Appeals were split on this argument, the case was certified to be sent to SCOTUS, and President Johnson, concerned the Court would side with Johnson, said "fvck it" and pardoned every single person involved involved in the rebellion.
And of course, schools don't teach this.
So let me ask you this: do you think the framers of the 14th would be cool with President Jefferson Davis? Haha, of course not. I guess it's a good thing he had a sense of shame and didn't do like Trump and run again.