Luck in gambling is unpredictable, but without basic knowledge (of course it is better if there is more of this knowledge) about blackjack, it is also impossible to win. I have an assumption that the probability of winning in gambling doesn't depend on luck or knowledge in particular, but in their combination. In what proportions, it is difficult to say, but if we cannot influence luck, then we can influence knowledge (their acquisition). Video courses can help us with this, for example.
In reality, luck is only unpredictable in the short term, not in the long term. That is why casinos can operate and make money, because of HE. If long term luck were unpredictable, casinos would not be able to operate.
A casino offering a double-or-nothing style game with 1% HE cannot predict what will happen when you bet $1 on a spin today, but it can fairly reliably predict that after 1M spins it will have won $10K.
For me these videos what can help is the gambler to play in a more rational way, having better results in the short term and losing less in the long term, but I doubt very much that they manage to teach to play EV+ as I said in the previous comment, and if so, I hope someone will prove it, but I doubt very much that they can do it and nobody replying in this thread has proven it so far.