A teleological argument that assumes truth is contingent upon a specific worldview would indeed be flawed, because it would make truth an artifact of a given perspective rather than something independent of it.
A scorpion, not knowing how to swim, asked a frog to carry it across the river. “Do I look like a fool?” said the frog. “You’d sting me if I let you on my back!”
“Be logical,” said the scorpion. “If I stung you I’d certainly drown myself.”
“That’s true,” the frog acknowledged. “Climb aboard, then!” But no sooner than they were halfway across the river, the scorpion stung the frog, and they both began to thrash and drown. “Why on earth did you do that?” the frog said morosely. “Now we’re both going to die.”
“I can’t help it,” said the scorpion. “It’s my nature.”
[1] I don't know how that's the republican's fault. Again, it's the constitution.
[2] This is entirely incorrect. Garry Wills, A Necessary Evil: A History of American Distrust of Government, Simon and Schuster, 1999, p. 252. ("Until recently, the Second Amendment was a little-visited area of the Constitution. A two thousand-page commentary on the Constitution put out by the Library of Congress in 1973 has copious annotation for most clauses, but less than a page and a half for the Second Amendment.")
The Tommy guns and explosives used during the gangster wars of the prohibition were almost entirely legally obtained (some were imported from Ireland in exchange for liquor). As a lawyer, what you are saying is literally the opposite of the truth. Until the 1980s, gun rights were understood to be a state's rights issue, and most limitations on the federal level (like in the Dredd Scott decision) were based around the rights of black former slaves to own guns.
[3] There is only a contradiction if you assume that the supreme court only exists to prevent the death of people and the unborn, rather than to enforce the constitution. If there was a constitutional amendment that said that every citizen had to go and kill a Mexican every Wednesday afternoon, it would be the job of the supreme court to enforce that constitutional provision until it was repealed.
The Supreme Court doesn't exist to impose your political views, it exists to impose the constitution. The constitution often produces outcomes that are not in synergy with each other or a broader overall purpose. That is the problem of the legislature and the constitution, not the court.
[2] The second amendment is a constitutional right. A textualist right wing Supreme Court would outlaw any restriction or regulation on firearms whatsoever. That would be entirely consitutional.
[3] There is no contradiction to the logic you describe. There is constitutional right to keep and bear arms. There is no constitutional right to an abortion. Even the supporters of the outcomes of Roe vs Wade admit it was a lousy opinion (e.g. Ruth Bader Ginsburg: https://www.law.uchicago.edu/news/justice-ruth-bader-ginsbur...).
If you want to create the right to an abortion, pass a law. If you want to repeal or modify the second amendment, persuade your fellow citizens to pass a constitutional amendment. An actual, activist right wing court could find most of the federal government unconstitutional, using the same logic Alito used in Roe vs Wade.
There are something like 3000 regulations on firearms in the US which the court has found to be consitutional which is debatable. Most of the Federal goverment, especially regulatory agencies are probably unconstitutional. Social security is probably unconstitutional, as it should be relegated to the states. RICO laws are unconstitutional.
If you create rights by judicial fiat, don't be surprised when they are removed by judicical fiat.
A teleological argument that assumes truth is contingent upon a specific worldview would indeed be flawed, because it would make truth an artifact of a given perspective rather than something independent of it.