Secondly, incorporation doctrine has made a giant mess of everything, especially the second amendment. It does need to be read in conjunction with the Militia clause in article 1 and you need to keep in mind the intent was to keep a small army but a powerful militia. Militia refers to every man capable of fighting. In federalist fashion, congress got to set standards but the states executed them. The second amendment was a minimum training standard that said congress couldn't abuse its power by enacting gun control because if they did, we'd have no militia to defend the nation which would be a perverse outcome. But basically the federal government has the (curiously unused) power to regulate the training of the militia. Part of that could plausibly include restrictions on how the militia is trained on certain weapons. Hence, to bear a WMD congress could require you to serve one weekend a month, two weeks a year if you get my drift.
Yes. But Congress has levied no such requirement. And absent any such requirement I should be able to successfully argue that if my right to bear arms extends to a Glock then there can be no Constitutional basis for arguing that it should not extend to a nuke.
My point is no one even attempts to make that argument because everyone knows it would get shot down on some obscure legal pretext because when push comes to shove no one is really a textualist or an originalist. It's all subtlety and nuance and interpretation and, ultimately, politics, even among people who insist that it is not.
As for the court's power to overrule, and to a certain extent, create law, that goes back to English common law and predates the US Constitution significantly.