I think an amendment would be needed if the entirety DC became a state, but if you carve out a small area for the federal district like this does I don't think an amendment is needed. An amendment should be passed after it becomes a state though to remove the 3 EV from the then depopulated federal district.
Better yet, give the 3 EV to the district and have the winner of the EVs determined by a fistfight on the Senate floor between the senators of each side.
Now we need to do a top 5 / bottom 5 power ranking.
Tester clearly an unbeatable titan.