Just a technical point here, but repealing the 13th amendment would not bring back slavery. For-profit prisons are in charge of that. Likewise, nobody would lose their voting rights if he repeals the 19th, until some state legislature said so.
EDIT: Plot for a novel: President Trump exhibits less and less lucidity, and there is talk of removing him from office. In response, his followers, many of whom are now judges, ram an amendment through exactly 38 state legislatures in the dead of a Saturday night, repealing the 25th Amendment. Weeks later, Vice President Pence and his drooling totem, Trump, go down in the same airplane with 13 lobbyists. Too late, everybody realizes there are no longer any rules of succession, and the First American War of Succession breaks out.
