The problem with the 2nd amendment isn't that it wasn't updated, it's that it was.

The 14th amendment incorporated the other amendments such that they did not only restrict the power of the federal government upon the states and citizens, as the founders intended, but also restricted the states (so you couldn't have southern states being evil to their citizens).

But the 2nd amendment was incorporated radically under Heller, when it should have been incorporated in a more moderate way, such that regulations were possible, within reason, not the wild-west that Heller imposed.

The 13th should have been reinterpreted by the courts such that many of our current forms of incarcerated service were considered beyond the line and became de facto slavery, particularly when imposed by southern states as they were.

Honestly the fundamental problem with post-bellum American jurisprudence was giving southern states any benefit of the doubt of being remotely human when they repeatedly violated every such standard.