Given that you clearly do not know what the term "well regulated" meant in 1791
I know exactly what it means. And the authors are clear that having a well regulated militia is necessary. Are you foggy about that, somehow?
They're also very clear, having stipulated that, just like with their British overlords had one, they're going to have a continually armed and well regulated military ... that they're not (UNLIKE their previous British overlords) going to let the necessary existence of that entity be an excuse to deprive the rest of the people from keeping and bearing arms.
telling people what the people who wrote the document *intended* is borderline delusional
What? They authors themselves, in a huge parade of letters, recorded debates, and supporting documents, explain exactly what they were thinking when it comes to the constitution and every one of its amendments. Those amendments didn't just cryptically appear and get signed, they were talked to death in congress and documented personal discussions, mused about in journals and letters, and openly debated. It was very clear they considered the personal right to own firearms to be paramount, and distinctly separate from the collective need to keep a well-regulated militia ready to go. Despite their allergy to a standing army of some flavor (having seen what they'd seen), they knew it was necessary to have that capacity always in place.
The existence of it being necessary, they knew that the temptation was going to be there for someone in military or civilian executive/legislative power to skew towards making that militia/military the only holders of armed power. Remember that the constitution is all about minimizing government power, and the amendments are there to remind everyone that even though they should know well enough from the structure of that charter that personal liberties are a hands-off affair, there are some areas (like political expression, assembly, arms, the sanctity of one's home, etc) that it was worth explicitly laying out as beyond the reach of government control. The linguistic construction of the second amendment may fall oddly on modern earns, but it really is simpler than most people seem to think: "The existence of an armed organization is necessary, but don't assume that the government's power to form and run such an organization gives the government the power to deny the people the right to themselves be armed."
Yes, "militia" had a very specific meaning at the time. Their urge to use that word was a reflection of how distasteful they found the notion of a large standing federal military (that being too close to their experience with British power). And it's precisely BECAUSE the assumed that the states and even more granular local powers would be taking on the responsibility to have armed groups under their control that they made the individual's right to be personally armed a fundamental, nationally protected right - to prevent a local government from becoming locally tyrannical (and likewise federally).
I don't think the early American government believed it could be specific and have these amendments stand the test of time (and they've been proven right over and over.)
Do you foresee a situation where the right to free expression or the right to assemble perhaps should be considered just a little too dangerous, and we should consider taking that away?
If so, you can start the process of putting a new amendment in place, one that kills of the First. While you're at it, you can try the same with the protections proclaimed by the Second (or the Fourth, if you think that's also a "living" amendment that's worth scrapping), but you're not going to get the supermajority and ratification needed to make any of that happen.