I understand your situation, but firstly, regarding your stuttering, you can reduce it by breaking up your words, speaking slowly, and breathing before speaking. Secondly, what the therapists told you about your condition not improving is 100% wrong. ،Because there is no specific standard that determines whether stuttering is permanent or not, from a scientific standpoint. From a practical standpoint, I am like you; my stuttering is severe and affects all letters, but I was able to reduce it and I sought therapy, even though I didn't I applied what he told me 95 percent of the time, but I improved. ،My message to you is to be kind to yourself, be optimistic, and look at the bright side. I know reality is tough, but you have no choice but to work.