I wouldn't be that worried about Vance, it's hard to find a less charismatic politician. Just a few days ago there was a grieving husband asking for some comfort and assurance that his wife didn't die in vain in the Iran war, that something will be done to prevent it from happening to anyone else. It's a real low hanging fruit for any politician. You just offer condolences, say you'll look into this (Vance could even collect some credibility by saying this is one of the reasons why he didn't want the war in Iran in the first place) and then thank them for their service (the husband was also in the military).
And it's clear Vance has been politically trained because he understood what he was supposed to do, but the way he went about it... Oh boy, it hurt me to watch it so I can't even imagine what the husband was feeling. Vance got the gist of what he was supposed to say but what came out could be summed up as "sorry your wife died bro, but this is the first time I'm hearing there are problems in the military" coated in the most HR speech you could have. And then he spent an uncomfortable amount time going into some really weird specifics about how they're trying to prevent this from happening again but that ended up coming across as "your wife died in vain because we didn't think before they got struck". And he didn't know when to end it. His own staff had to cut him off to get him out that low-hanging fruit he jury-rigged into a political mine that he threw himself onto. You could take a literal stranger from the street and there's a high likelihood that stranger would've given a better answer than Vance.
And this is why I'm not worried. Because the republican party is held together by the only strength Trump has, his charm. Now before you're going to say Trump can't have any charm because he's a deplorable rapist whose cognitive capacity is in the red, look at his voters. They're morons. Trump literally said he could say the stupidest thing and they would cheer for him. And they cheered for that. His voters don't know what he's doing or saying or anything. All they see is how he present himself and he presents himself in a way where his voters think he knows what he's doing. That's the only thing keeping the party together and that requires a certain level of presence and charm. Vance has none of that. Trumpists won't rally behind Vance because he looks like he enjoys getting cucked by his wife, he talks like he's a liberal consultant and he has no spine when it comes to taking some accountability. In many ways he's the very embodiment of the democrat politician every republican voter hates.
I don't know what kind of a political brainwashing the republican party needs to do to get the republicans to support Vance. Or maybe they'll just hollow out Vance and use him as a sock puppet because that would actually improve his charisma.