> There is zero evidence he meaningfully disagrees with Trump on anything of consequence
What I just said above is evidence, I think. There certainly isn't zero evidence.
> Do you really think anyone donates $132 million dollars to something they aren't fully bought in to?
Yes — absolutely. People make compromises all the time, and employ strategies that exchange short-term (even reputational) cost for long-term benefit.
> When someone shows you who they are, you should believe them.
He has shown us who he is, so far, by his actions in building companies and promoting rationality and science. Yes, he's also recently gone down the rabbit hole of nonsense on Twitter, but for now I don't think that fully represents his underlying nature.
I have no particular dog in this fight. I'm not American and nor do I have any particular love of Musk. However, I think you're overreacting.
As for your source: I know how much he's donated, and it is a shocking amount. However, in the wake of Trump's re-election, the share price of Tesla has just gone up 15% making Musk $15 billion richer. Makes that $132 million seem like pocket change. At worst, he's a self-interested opportunistic capitalist. But he's not a moron or a religious zealot as others are.
I expect he will either indeed be a moderating influence on the administration (remember this is in the context of Trump; I'm not saying he counts as a moderate in the usual sense) or will quickly lose favour or otherwise become disenchanted with Trump and Trumpism and vacate whatever position he's granted and move on.
Also remember: I'm not arguing he's particularly sensible or even acts like a grown up (he doesn't). I'm arguing that he's not 'literally Hitler' as some seem to be insinuating.