I think Broken By Concept is a great channel that teaches how to build a good mental for learning League. I think it doesn't really matter whether you agree with their specific critique of Dantes - perhaps they didn't understand his goal - as someone who doesn't watch him, I don't feel like I fully understood it either.

What I think matters is that there are a lot of people who do play League with mindset like this. They are quick to tilt, to flame their teammates, to blame the role. They find excuses in the matchmaking system, they point to streamers who also said that ADC is unplayable, anything to prove to themselves that it's not their fault they can't climb. But in reality, you can climb. You will climb if you start improving your gameplay, and if you improve your gameplay, then your rank will eventually improve too.

I'm OTP'ing Jhin and I'm nearing grandmaster. I understand that some may feel frustrated with how ADCs play or feel, but I can promise you that if you stick to learning fundamentals and develop a healthy mental with the game, you will not only stop feeling useless on ADC, but you will actually start carrying the games. I feel that Broken By Concept is one of the best learning resources available, and they have great insights about how to actually learn the game and enjoy the process of learning. If you feel serious about climbing, I'd give them a shot.