I think that the OP can give some proves private(but i don`t sure that it will be proves and not a scam try). It is to silly to try to scam in such a way. But the same time we saw so different scams that it is possible even such a try. Anyway i`m sure that such courses(even if it is true) can be useful only for pro-gamers and they know each other and can understand is it truth or not. For common poker player there are enough free courses.
I think the same as you, to do a poker course you only need to have a YouTube account and there are many who want to get followers and they can do it there, and there is a win-win exchange, where the Youtuber benefits and the person in question also because he learns, so this is something that I find difficult to believe when they want to give a course and it is paid, the only way is that the one who offers the course assures the person that they will always have profits, because they will give the best advice of people who are veterans in the game, and I think that even so it is not profitable, because everything depends on the person who receives it and how they think.
I think that nobody can guarantee you the profit after any courses. There are lots of moments that gives you or your opponent chance for winning. One of them is skill surely and you can improve it by courses. But i can`t even imagine what information you can get in the OP courses and why it costs money. I think that the OP can share some information and after that we can understand is it possible to find it for free or not.