So if a State put into its Constitution that no one in that state had to pay federal taxes, or serve in the U.S. armed forces, that would be enforceable? Nonsense. Article VI quite clearly says that the U.S. Constitution and federal laws are supreme over any State Constitution. And the federal courts have been exercising their power to strike down state laws as unconstitutional since at least Martin v. Hunter's Lessee, which was back in 1816.
The states specifically granted powers long ago to tax incomes and raise armies to the federal government.
They granted no power to define marriage.