Dredd Scott was decided in 1857. That’s a long time after the Constitution.
“But the Constitution can only be amended”
Nope. Study US civics. The Constitution can be amended, which is unlikely — and also interpreted by the Supreme Court, which is what one of its key purposes is.
Whether you know the intent of the framers regarding the second amendment or not [you don’t, it is clear you don’t know how to read it], the courts get to evaluate and reevaluate how to interpret the Constitution and legal precedent.
Too bad it sounds like once again you are on the wrong side of a history you disturbingly misunderstand.