Yes it’s possible to effectively solve the stutter/ holding back but the change is the hardest part because you literally have to change your thinking, beliefs and perceptions too. I’ve heard of a guy who made blocks completely disappear by imitating how a celebrity talks and behaves. You never stutter when you talk in an accent or when you sing because it’s not you talking, the you that holds back disappears. I recommend you search the stuttering hexagon by John Harrison to understand what am talking about. The stuttering hexagon is a model where stuttering is viewed as a system of six interconnected components, including speech, emotions, beliefs, perceptions, and more.