There are two kinds of right-wing politicians. Grifters who will say and do anything for personal gain, and suckers who have come to believe it. Vance is just a grifter, make no mistake. And maybe at one point Trump built his empire through grift - he was a Republican in 1987, Independence Party in 1999, a Democrat in 2001, Republican again in 2009. But at this point Trump's narcissism has led him to fall for his own grift, he does believe it.
You can actually tell with Trump that the one issue he doesn't really care about at all but has to pander to his base with is abortion. And when you see how he flounders when asked about Roe v Wade, that gives you a baseline to compare to all the other shit that comes out of his mouth that he's dead serious about.