Elon's heel turn from visionary to world-class piece of shit has been something else.
Money and power almost always corrupts a person.
It's not really that much of a 'turn'. He's always been a greedy, manipulative asshole. He's employed questionable tactics in building his fortunes, some of the earlier companies he left did better because of him leaving (at least in the short-term). If you look at his families legacy there's questionable 'blood money' in the gemstone mine of his Father and his success from the apartheid-era. Something that earlier on Musk admitted to his Father's wealth and the privilege it afforded him. He bragged about the private jet flights and everything.
Then as it became more questioned about he suddenly started the stories about distancing himself from his Father and his wealth. I think some of the earlier stories about Musk even got 'scrubbed' from the news sites that originally ran them even though it was him GIVING THE INTERVIEW and admitting the stuff. Guess having billions will give you a lot of pull.
But really this all boils down to he grifted against the 'left' for pretty much as long as he possibly could and now he's deciding to move to the right and grift there. I don't think there was any change in his actually personality or anything, it's just all about money.
The whole shtick about Tesla/EV saving the environment and mankind has kinda run it's course, so now he's trying to get the 'other side' onboard with him fighting 'against tyranny' and all this other crap.