Elon was always problematic. His increasing social media use removed the natural filters that prevented people from seeing it.
To me, Musk crossed from "maverick" to "problematic" around 2018, when he tried to insert himself into the Thai cave rescue operation and ended up slinging accusations of pedophilia on Twitter.
At this point, he has unlocked many more specific adjectival achievements, and those are the ones that should be invoked whenever Musk's behavior is the topic. (Which it isn't here.)
They now provoke instinctive revulsion when used in culture-war-adjacent contexts even when, as here, their usage is entirely legitimate (you presuppose a vague but mutually understood allegation rather than nebulously introducing a fresh one). I think only “controversial” has escaped this fate, but it might be too weak for your purposes.
(To be clear, I am only trying to explain why your phrasing might cause your interlocutor to momentarily recoil even when—as in my case—they don’t actually have any problem with the contents of your statement. What you do with this explanation is up to you: I don’t believe these terms are short-term salvageable at this point, but neither will I begrudge others their choice of hopeless cause; I certainly have my own fair share of those.)
Musk is easy to laugh at and to criticize. Problematic encompasses his lying, pettiness, racism, sexual weirdness, ego and fraud as well as anything. Regardless of the proportions of specific traits, as a whole, he’s a problematic individual. That’s perfectly cromulent.