I always sort of assumed as much. For one, there is something about Mr Beast giving me bad vibes, I think he kind of gives off psychopath vibes. Maybe it's the eyes. I've also heard people who have interacted with him talk about how he spends basically all his time thinking about attention economy and views and just... it doesn't sound healthy.
But also, yeah no shit he basically does reality TV on steroids. And reality TV has been fake ever since they first figured out it's better TV than boring actual reality. So it tracks that his videos are also fake.