There are different severities of stuttering. A more impactful stutter often means a more damaged sense of self. People who have spent their life feeling inferior need more than just “you can do it!” If this sound mean or bizarre to you, try understanding that you have a resilience that others do not. People have different internal biologies, different social suppprts, etc. what works for one may not work (or be harmful) to others. As difficult as stuttering for a few years is, stuttering for most of your life presents a bigger challenge - which is harder to overcome.