There's the reported bloody noses... That's evidence of something. In that short span of time though? When you take into account the frequency of the nose bleeds and time frame, the chances that is related to snorting drugs goes up. So to say there is no evidence is erroneous.
Elon is diagnosed with Asperger's - so he might actually be on drugs in the form of medication. RFK Jr is probably on various supplements but I'd say it's probably not drugs or steroids.
But you think what you want to think... That's the idea of free speech.