I think that making someone addicted to youtube would be harder, than simply slowly radicalizing them into a shunned echo chamber about a conspiracy theory. Because if you try to make someone addicted to youtube, they will still have an alternative in the real world, friends and families to return to.
But if you radicalize them into something that will make them seem like a nutjob, you don’t have to compete with their surroundings - the only place where they understand them is on the youtube.