Fine. Be territories before being admitted as states. Go through the formality. What provision in the Constitution places a time frame on how long a land mass must exist as a territory before it can be admitted as a State? If none, it could be as simple as signing a territoriality agreement immediately followed by admission into the Union as a petition for Statehood. As someone wrote elsewhere on this thread, when the US was founded and still functioning under the Articles of Confederation, there was a provision for Canada to be able to freely join the US if it so chose, and to do so without requiring further permissions from the colonies.

Your point does not materially impact the substance of what my proposal is.