Should I follow Brian Dean and his courses?

I am a beginner in SEO, and I am trying to learn it with a focus on content writing since I am interning in this field right now. I was following a few courses by Brian Dean in SEMrush. I tried a popular crash course by this man, and I liked how it was catchy, well-delivered and easily understandable. But a senior suggested me, more like taunted me to not follow Brian Dean (or any other person) just because they are popular and seem authentic. She isn't entirely wrong, but his courses do not seem too commercial (as said by my senior). It looked okay to me, and I wished to follow him but now I am confused. Through this post, I want to invite discussions about this, and for some valuable tips.