How do we know adam does youtube fulltime? has he ever said that?
I think he has said that in a vlog from a few years ago. He did used to work for Disney, not just at the parks but also in the London based office. He obviously didn't give much information away about where the office was, aside from it was Disney and he was leaving it to pursue something else.
If he were to work somewhere else, I think he would have mentioned it in passing, given all the fingers in pies he had got for himself currently, his Youtube, the clothing line, the podcast, the merch, his books, working with a travel agents, I just don't think he has the time to do anything else.
(am being sarcastic here, but were it someone who was a bit more dedicated, I could imagine that would all take up more time and indeed effort, rather than just two or three episodes of a podcast and giving up, a few books that haven't been properly edited, clothing that are 'meh', a travel agents that also need their website carefully combed over, and a youtube channel that needs a lot of tlc.)