I know exactly what you're going through so hold on, my friend, there's always hope. I had 30+ years of stuttering and it stopped in my mid 40s over a year or two. I don't know why it stopped and don't work too hard to discover why. As you have a large tongue work to strengthen the tongue muscles by diction/elocution lessons, simple exercises found on YouTube. The same ones professional actors and newsreaders use.