> What should I read, watch or listen to in order to catch up on today's approach to selling, do you have some recommendations?

It really depends on where you are in this journey.

  Seth Godin
    Permission marketing
    Tribes: We need you to lead us
    All marketers are liars
    This is marketing
    Etc.
  
  Ries & Trout
    Positioning: The battle for your mind
    The 22 Immutable Laws of Marketing
    Etc.
  
  Scientific Advertising - Claude Hopkins

  https://www.foundingsales.com/
  
  The Little Red Book of Selling - Gitomer

Learning to use online channels, in my opinion, requires a lot of work. Companies like Google have useful material. Frankly, this subject is wide and deep. I got into it starting about twenty years ago.

Perhaps others can suggest books or courses/videos on best practices for online marketing and optimization that are more up to date.

I'll warn you that at some point in my journey I hated the fact that I had more business books by my bed than engineering books. It was frustrating until I reached what I call "cruise altitude" and had enough capabilities and understanding to do well.