It cannot be because constitutionally prez and VP must be from different states
That is not true.
Constitutionally (12th amendment), electors to the Electoral College must vote for at least one candidate who is not from the same state as themselves.
Trump and DeSantis can run on the same ticket, but the electors in Florida can only vote for one of them. Florida electors would be forced to split the ticket and vote for the Democrat VP nominee (or vice versa).
So your statement is effectively true that it is impractical to have both the President and VP nominees from the same state, but it is not unconstitutional to do so.
-PJ