I think it’s the drugs. He used to be at least somewhat sensible. In recent years he’s just been acting totally bonkers. But having unchecked power will do that to you too, of course.
Well, drugs is obvious, but covid is also known to cause cognitive issues: https://theconversation.com/long-covid-puzzle-pieces-are-falling-into-place-the-picture-is-unsettling-233759
I mean there were some signs earlier (of course those who know him will say he always was an asshole, but at least he was better at masking it) it was 2020 when he went full bonkers.