I think it’s useful to read “A well regulated militia, being necessary to the security of a free state” as a bit of salesmanship.
Recall that the Bill of Rights was added to the constitution to get it ratified; some critics feared that the federal government could trample over certain rights, and so express provisions were added to make it clear what limits it had.
Among those were rights assured to the States. And those states, with regard to the military, had 2 major fears. One was that a standing federal army could invade their state, and the other was that a state without its own military force might be powerless against an insurrection within its borders.
The 2nd amendment was a promise that this wouldn’t be a concern. It is basically saying “You need a military to protect your sovereignty so the federal government can’t take that away.”
But it should also be remembered that the Constitution, and its amendments, applied to the federal government - it was only later that the Supreme Court started applying these rights to state action.
So, as originally written, the 2nd amendment didn’t assure a person the right to keep and bear arms vis a vis the state. Rather, it was the federal government that couldn’t remove that right. No reference to a state prohibition applied, and so none should be inferred. If a state decides it wants to disarm its citizens, the U.S. constitution doesn’t say it can’t.
(Ultimately, the cynic in me says that this ‘promise’ to the states related, as much of the document does, to slavery. Why would the federal government invade a state if not to free its slaves? And why would a state need to quell insurrections if not because slaves were revolting? In this reading “the security of a free state” is a reference to a state’s ‘freedom’ to maintain slavery).
So, no, not an individual right, but a means of limiting federal power at a time when the country was suspicious of standing armies.