That looks like an Odachi sword. Which was normally back mounted and quite impractical. It was mostly used by samurai against cavalry, though Yari (spears) used by the common man were far more practical. The Odachi didn't last long and was rarely used in battle. Though there's a couple of notable exceptions in the later Sengoku period.
I've trained with one a few times. It's absolutely ridiculous to use.
My money is on Shapiro. He has the sword of course, but I get the sense that he is a smart guy who just plays a stupid guy on TV, unlike Elon who is the other way around
I don't get the impression that Shapiro is putting on an act. I think he mostly believes the outrageous things he says, and when he doesn't it's because he's confident he can use his debating skills to muddy the waters.
With Musk, I think he's just a ruthless bully. I think he breaks laws, breaks norms, ignores morality, etc. and assumes he can get away with it. If he doesn't get away with it, his money will get him out of it, or he'll arrange for someone else to take the fall.
For something like this, look at what happened with Zuckerberg and the supposed cage match. Musk refused to back down, but also refused to commit. I bet he'd agree to some kind of death match, but then he'd keep changing the rules, or the venue, or the time. Meanwhile, I bet Shapiro would try to make a contract with some kind of sneaky clause in it that technically allowed him to have a relative fight on his behalf or something.
Neither .... first physical touch between each other and both would fall over into a fetal position accusing the other of unfairly starting the fight when they weren't ready.