It's difficult to gauge why Sunak does what he does, he's just very bad at politics, at every level. Theresa May was poor but she was a politician, she wasn't unhinged, nothing she did was a mystery, there was a logic to it, even if you disagreed with it, but Johnson, Truss and Sunak, in their different ways, are damaged individuals.
These three arseholes are a product of a sick party, an irresponsible party, in hoc to a divisive fantasy ideology completely at odds with the daily lives of ordinary people. They operate in a parallel world that exists entirely in their head, it's why nothing they say or do makes sense. These Tories and not worthy of government, they're a Poundland version of the Republicans in the States.
The venality of Johnson and the madness of Truss are beyond dispute, but Sunak is difficult to pin down, there's something dead about him, he's like one of those pod people in Invasion of the Body Snatchers.