Do you have a source for this? My understanding of the second amendment comes from reading America’s Constitution: A Biography by Akhail Reed Amar. I’m trying to find reference to this meaning you cited, but coming up short. I also don’t find it in the article by him in The New Republic:

https://newrepublic.com/article/73718/second-thoughts

DC vs. Heller settled the meaning of the term in regards to Constitutional law. There's also a long history of "well-regulated" meaning well-equipped, in proper working order, etc. in English going back hundreds of years.

A quick search found this list of examples: https://www.learnaboutguns.com/2019/08/11/the-meaning-of-wel...

(linking to that site rather than its source since the source is sending a bad SSL cert)

There are other writings by the Founding Fathers from the time of the ratification of the US Constitution reiterating the need of a right for people to own arms in case it's necessary to overthrow the government, specifically including the government they had just created.

Thanks! I’m trying to round out my understanding. I’m not too big of a fan of textualism/originalism, but it’s a major judicial theory (obviously).