Regarding Elon:
I, too, am worried about a billionaire with active stake in high-level-security companies having an admin role in the government. Someone asked earlier, but I didn't see it answered...do the same laws apply to Elon in terms of divesting interest during active governing? Mark Cuban was actively campaigning for and seeking a position in the Harris admin. People on the right would hate that. My general rule of thumb is to not tie my rooting interest to any billionaire, regardless of who's "team" he/she is "playing for."
Elon talked about how Biden's DOJ is going after him and explained in detail how insane it was. Taking him at his word, it does sound unbelievably batshit crazy, but I don't know any further details on the matter so it's hard to have any strong opinion regarding this particular case. Regardless, one would have to assume that human nature will take over and greed, ego, etc and the office will be used to his benefit. This should be alarming and at the very least warrant a close eye.
As far as X goes, it's entirely open sourced for transparency. I personally am a firm believer in free speech and I cringe at the idea of censorship, "disinformation" laws, etc. If/when you see throttling of liberal views and censorship on X, then let the freak out ensue. Until then, he should just divest and let someone else run it temporarily like any other company.