To me, the “well-regulated milita” became a moot point in the 19th century when all of the state militias were unified into the National Guard and state defense forces. The term was never intended to include private militias, as evidenced by the fact that in 1886, the Supreme Court concluded that militias are not constitutionally protected and that states have the right to ban them altogether (Presser v Illinois). So any state can choose to have their own militia or they can choose to prohibit them all together. It clearly shows that militias are under the control of the states.
The 2nd amendment never once mentions private gun ownership, so it seems more like the right to bear arms was always intended to be a right of the individual states, not a right of private citizens. I have no clue how we got to the point that we are currently in with 2A somehow protecting private ownership of assault rifles other than to blame corporate lobbying and institutional corruption.