Point 1: Why would he agree to that, at such huge personal cost? He's paying the Saudis almost a billion a year for the loans they gave him. He's getting the world's shittiest deal here. Unless they have some kind of truly epic blackmail on him (the kind that billions upon billions of dollars couldn't successfully erase) there's literally no possible motivation for that. If the Saudis were bankrolling the whole operation and he was just the point man your theory would make sense, but as it is he's the money and the mook. He's getting nothing here.

Point 2: If Musk was knowingly destroying Twitter, why would he attach the X branding to it? X has been Musk's personal baby for decades. He lost PayPal over it. He genuinely believes it's some kind of brilliant, genius idea, his "everything app" for finance that will revolutionize the world. If he was trying to kill Twitter, he would kill it as Twitter. If you want to burn your business down for the insurance money, you don't lock your kids inside first (metaphorical kids, the kind you genuinely love, not his actual kids who hate him). If he destroys Twitter as X then he destroys X, and there's no possible benefit to that.