Giving DC statehood is not creating a new state, it is abolishing the Seat of Government of the United States.
Article 1 Section 8
To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the Acceptance of Congress, become the Seat of Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings;
Congress would have to cede the power to make laws for the Seat of Government. This would require an amendment to the constitution.
It would probably be easier to give DC a senator and representative by amendment that to make it a state.
I’m guessing that if DC statehood goes forward it would not include the areas of federal infrastructure such as the White House and Capitol building. It would only include residential areas.