One structural point about Section Three that is not getting enough attention is its limitation on the President's pardon power. Only Congress can give an insurrectionist amnesty. There was an amendment proposed in the Senate in 1866 to let the President give amnesty with a pardon. The proposal was rejected. Congress reaffirmed this point in 1885. When the Attorney General issued an opinion saying that Section Three could be waived by a pardon, Congress rejected that view and insisted on its exclusive power.
This amnesty limit makes it harder for the President to support an insurrection against the Constitution. He can pardon participants of criminal charges but cannot exempt insurrectionist officials from accountability. Interpreting a provision that makes it harder for the President to support an insurrection as exempting a President who leads an insurrection doesn't make much sense.